DEPARTMENT   OF   THE    INTERIOR 


MONOGRAPHS 


OF    THE 


UNITED  STATES  GEOLOGICAL  SURVEY 


VOLUME    VIII 


WASHINGTON 

GOVERNMENT    PRINTING    OFFICE 

1  884 


UNITED    STATES    GEOLOGICAL    SURVEY 


J.  W.   POWELL  DIRECTOR 


PALEONTOLOGY 


OF 


THE    EUREKA    DISTRICT 


By    CHARLES    DOOLITTLE    WALCOTT 


WASHINGTON 

GOVERNMENT     PRINTING     OFFICE 

1884 


Bancroft  Library 


DEPARTMENT  OF  THE  INTERIOR, 

UNITED  STATES  GEOLOGICAL  SURVEY, 

Washington,  D.  C.,  June  1,  1884 

SIK:  Herewith  I  have  the  honor  to  transmit  a  report  on  the  inverte- 
brate fossils  of  the  Paleozoic  rocks  of  the  Eureka  District,  Nevada. 

I  am  greatly  indebted  to  you  for  the  personal  interest  you  have  taken 
in  the  work  and  generous  facilities  given  me,  both  in  the»  field  and  office,  in 
carrying  on  the  earlier  part  of  this  investigation. 

I  am  also  under  many  obligations  to  Hon.  J.  W.  Powell,  Director  of 
the  Geological  Survey,  for  the  opportunity  afforded  me  to  continue  and 
enlarge  the  work  after  the  completion  of  the  original  report. 
Very  respectfully, 

CHARLES  D.  WALCOTT. 
Mr.  ARNOLD  HAGUE, 

Geologist  in  Charge. 


UNITED  STATES  GEOLOGICAL  SURVEY, 

New  York,  June  4,  1884. 
SIR:  I  have  the  honor  to  transmit  herewith  the  report  of  Mr.  Charles 
D.  Walcott  on  the  "Paleontology  of  the  Eureka  District." 

The  publication  of  Mr.  Walcott's  monograph  marks  an  era  in  the  his- 
tory of  the  Paleozoic  paleontology  of  the  Far  West.  Heretofore  the  col- 
lections of  fossils  obtained  have  been  in  most  instances  small,  incomplete, 
and  hastily  gathered  from  more  or  less  widely  separated  localities.  If  the 
species  obtained  proved  sufficient  to  determine  the  geologic  horizons  for 
the  purpose  of  comparative  study,  little  more  was  expected. 

Now  we  possess  the  results  of  a  careful  survey  of  a  district  with  a  rich 
fauna,  through  30,000  feet  of  Paleozoic  strata,  representing  the  Cambrian, 
Silurian,  Devonian,  and  Carboniferous  rocks. 

Mr.  Walcott's  intimate  knowledge  of  the  geological  and  structural 
features  of  the  district  lends  additional  weight  to  his  own  special  labors. 
I  regard  his  report  as  the  most  important  contribution  yet  made  to  the 
invertebrate  paleontology  of  the  Basin  Ranges,  and  of  great  value  in  its 
bearings  upon  the  geology  of  the  Cordillera,  which  under  your  guidance 
we  are  gradually  working  out. 

Very  respectfully,  your  obedient  servant, 

ARNOLD  HAGUE, 

Geologist  in  Charge. 
Hon.  J.  W.  POWELL, 

Director  United  States  Geological  Survey,  Washington,  D.  C. 

vii 


PREFACE. 


This  volume  includes  a  report  on  the  fossils  collected  during  the  field 
season  of  1880  by  the  members  of  the  Geological  Survey  of  the  Eureka 
District,  transmitted  for  publication  May  lr  1882,  and  additional  observa- 
tions and  descriptions  resulting  from  the  study  of  collections  made  under 
the  immediate  direction  of  the  writer  in  the  summer  of  1882.  Eleven 
plates  of  illustration  and  nearly  double  the  amount  of  text  originally 
transmitted  have  been  added,  and  the  character  of  the  report  slightly 
changed.  The  reader  will  pardon  the  slight  confusion  in  the  arrangement 
of  the  plates  resulting  from  this,  and  also  the  difference  in  the  mode  of 
illustration.  The  system  of  using  wood-cuts  is  of  great  advantage,  as  it 
offers  an  opportunity  to  all  for  obtaining  copies  of  the  original  figures 
by  electrotyping.  This  is  the  first  extended  trial  of  the  method  for  fine, 
detailed  illustration,  and  is  attempted  at  the  special  request  of  Major  J. 
W.  Powell,  Director  of  the  Survey. 

In  the  preparation  of  the  original  report,  frequent  reference  was  made 
to  the  well-known  Hall  collection  of  Paleozoic  fossils  in  the  American 
Museum  of  Natural  History,  through  the  kindness  of  the  curator  in  charge, 
Prof.  R  P.  Whitfield,  to  whom  I  am  indebted  for  valuable  assistance.  Prof. 
James  Hall  generously  gave  access  to  the  material  he  had  accumulated  for 
the  study  of  the  corals  and  lamellibranchiate  shells  of  the  Devonian,  and  also 
aided  me  in  my  comparisons  between  the  New  York  and  Nevada  speci- 
mens. Acknowledgment  is  due  Prof.  Samuel  Calvin  and  Dr.  J.  P.  Farns- 
worth,  of  the  State  University  of  Iowa,  for  the  use  of  specimens  for  com- 
parison. The  skill  and  care  exercised  by  Mr.  G.  B.  Simpson  in  preparing 
the  drawings  for  plates  ix  to  xx,  inclusive,  and  by  Dr.  J.  C.  McConnell  for 
plates  i-viii,  xxii-xxiv,  inclusive,  is  shown  in  the  plates  illustrating  this 

report. 

C.  D.  W. 


CONTENTS. 


Page, 

etter  of  transrnittal  to  Mr.  Arnold  Hague,  by  the  author v 

Letter  of  transmittal  to  the  Director,  by  Mr.  Arnold  Hague vii 

Preface ix 

Summary  of  results 1 

Fossils  of  the  Cambrian 11 

Observations  ou  Olentllus  Howelli 32 

Fossils  of  the  Lower  Silurian 65 

Fossils  of  the  Devonian 99 

Fossils  of  the  Carboniferous 212 

Systematic  list  of  species 268 

Paleozoic  section  in  Central  Nevada 283 

Index 286 

xi 


ILLUSTRATIONS 


PLATE  I. — Cambrian  and  Silurian  fossils. 

II. — Devonian  fossils. 
III. — Devonian  fossils. 
IV.— Devonian  fossils. 
V. — Devonian  fossils. 
VI. — Devonian  fossils. 
VII. — Carboniferous  fossils. 
VIII. — Carboniferous  fossils. 
IX. — Cambrian  fossils. 
X. — Cambrian  fossils. 
XI. — Silurian  fossils. 
XII. — Silurian  fossils. 
XIII. — Devonian  fossils. 
XIV. — Devonian  fossils. 
XV. — Devonian  fossils. 
XVI. — Devonian  fossils. 
XVII. — Devonian  fossils. 
XVIII. — Carboniferous  fossils. 
XIX. — Carboniferous  fossils. 
XX. — Carboniferous  fossils. 

-  XXI. — Outline  figures  of  Olenellns  and  Lingula. 
XXII. — Carboniferous  fossils. 
XXIII. — Carboniferous  fossils. 
XXIV. — Carboniferous  fossils. 


Fid.  1. — Cross-section  of  Ortboceras 

2. — Cross-section  of  Ortboceras 

3. — Section  of  BelleropJion  majusculus 

4. — Outline  figure  of  Ampullaria  ?  Powelli 

5.— Operculnm  of  Ampullaria  ?  Powelli 

G. — Outline  figure  of  Physa  prisca '..... 

7. — Outline  figure  of  Zaptychius  carbonaria 


Page. 
87 

87 
257 
261 
261 
202 
262 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


BY  CHARLES  D.  WALCOTT. 


SUMMARY  OF  RESULTS. 

The  general  character  of  the  fauna  of  the  Cambrian,  Silurian,  Devo- 
nian, and  Carboniferous  strata  of  the  Eureka  and  White  Pine  Mining 
Districts  of  Central  Nevada  is  given  in  this  report  more  to  illustrate  the 
stratigraphic  succession  and  equivalency  of  the  geologic  horizons  with 
those  described  elsewhere  than  as  a  detailed  monograph  of  the  inverte- 
brate fossils;  since,  for  the  latter  purpose  much  more  extensive  collec- 
tions are  necessary  to  represent  the  large  fauna  of  the  Paleozoic  system  of 
Central  Nevada  than  we  have  at  present. 

As  an  assistant  geologist  in  the  field-work,  the  writer  collected  most  of 
the  fossils  in  situ,  and  studied  their  mode  of  occurrence  and  stratigraphic 
relations,  thus  disposing  of  an  element  of  uncertainty  which  frequently 
arises  in  the  mind  of  the  paleontologist  when  examining  collections  from  a 
region  unfamiliar  to  him,  and  which  presents,  in  the  strata  of  the  lesser  divis- 
ions of  its  great  geologic  series  of  rocks,  associations  of  species  unknown 
elsewhere  or  an  unusual  vertical  range  of  individual  species.  The  presence 
of  the  Trenton  species  Orthis  testudinaria  in  the  upper  portion  of  the  lower 
half  of  the  Pogonip  Group  in  association  with  the  genera  Ptychoparia, 
Dicellocephalus,  and  Asaphus,  is  a  typical  example.  Other  illustrations 
of  unusual  association  of  species  will  be  given  in  speaking  of  the  Devonian 
fauna. 


2  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

In  the  lowest  fossiliferous  stratum  of  the  Cambrian  in  the  District  an 
interesting  species  of  the  genus  Olenellus,  0.  Howelli,  occurs  that  exhibits 
several  abnormal  features  of  development,  and  also  certain  embryonic 
characters  that  show  the  relation  of  the  genus  to  the  genus  Paradoxides. 
Considerable  space  is  given  to  the  description  and  discussion  of  this  species, 
and  also  a  plate  of  outline  figures  to  illustrate  its  variations  and  relations  to 
other  species.  The  specific  identity  of  two  of  the  three  species  of  Olenel- 
lus, with  0.  Gilberti  and  O.Howelli  from  Pioche,  Nevada,  130  miles  distant, 
and  their  close  resemblance  to  the  species  of  Olenellus  occurring  in  Ver- 
mont and  Newfoundland,  closely  unites  the  faunas  of  the  widely-separated 
localities,  and  aids  materially  in  the  con-elation  of  the  different  groups  form- 
ing the  Cambrian  system  on  the  North  American  continent. 

The  Lower  Cambrian  type  of  the  Conocephalidse  is  represented  by 
Ptyclioparia  Linnarssoni  and  P.  Prospectensis  ;  and  the  subgeneric  groups  of 
the  genera  usually  occurring  in  the  Potsdam  Group  are  prominent  in  the 
fauna  of  the  upper  portion  of  the  Cambrian.  In  Protospongia  fenestrata  we 
have  a  very  simple  and  peculiar  form  of  silicious  sponge  that  is  probably 
identical  with  the  Cambrian  species  of  St.  David's,  Wales. 

Much  remains  to  be  done  with  the  small  brachiopods  of  the  Cambrian 
and  Lower  Silurian,  since  from  their  minute  size  and  the  imperfect  state  of 
preservation  of  the  specimens  collected,  correct  generic  and  specific  refer- 
ences are  very  difficult.  The  one  species  of  the  genus  Graptolithus  in  the 
upper  portion  of  the  Pogonip  (Quebec)  Group  is  the  only  trace  discovered 
at  this  horizon  in  the  Eureka  District  of  a  fauna  which  the  writer  in  1882 
found  quite  extensively  developed  in  the  Pifion  Range  to  the  north.  The 
Graptolites  from  Belmont,  Nevada,  that  were  described  by  Dr.  C.  A.  White 
and  referred  by  him  to  the  Utica  slate  horizon  of  the  Trenton  Group  (Expl. 
and  Surv.  West  of  1 00th  Merid.,  vol.  iv,  part  1 ,  p.  10),  are  probably  from  the 
horizon  of  the  Quebec  Group,  or  the  Upper  Pogonip  of  the  Eureka  section. 

The  succession  in  the  faunal  series  from  the  Olenellus  (or  Middle  Cam- 
brian) fauna,  through  a  large,  well-defined  fauna  of  the  character  of  that  of 
the  Potsdam  Group  of  New  York  and  the  Mississippi  Valley,  to  One  that  in 
its  assemblage  of  species  combines  both  Cambrian  and  Silurian  types  and 
passes  upward  into  a  fauna  comparable  to  that  of  the  Quebec  Group,  or  the 


SUMMARY  OF  RESULTS. 

Calciferous  and  Chazy  Groups,  is  of  special  interest.  The  transition  from 
the  Cambrian  to  the  Silurian  fauna  is  very  gradual,  and  such  as  would  occur 
where  there  was  no  marked  physical  disturbance  to  influence  the  faunal 
change  resulting  from  the  natural  dying  out  and  development  of  species  or 
the  influx  of  new  species  from  other  areas. 

Of  the  species  occurring  below  the  passage  beds  three  are  identical 
with  species  occurring  in  the  Potsdam  sandstone  of  Wisconsin,  viz:  Hyo- 
lithes  primordialis,  Dicellocephalus  Osceola,  and  Ptychaspis  minuta;  one  with 
Acrotreta  gemma  of  the  Calciferous  formation  of  Newfoundland;  and  Pty- 
choparia  Oweni  is  a  common  species  of  the  Potsdam  horizon  in  Montana 
and  Dakota.  These  specific  identifications  and  the  great  development  of 
species  of  the  genera  Agnostus,  Dicellocephalus,  and  Ptychoparia,  in  the 
middle  and  upper  portion  of  the  Cambrian  section,  furnish  abundant  evi- 
dence upon  which  to  correlate  the  fauna  and  the  geologic  horizon  at 
which  it  occurs  with  the  Potsdam  fauna  and  formation,  as  was  done 
by  Messrs.  Hall  and  Whitfield  (Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p. 
199,  1877).  Of  the  Potsdam  fauna  eleven  genera  and  fifteen  species 
continue  on  into  the  passage  fauna,  viz  (species  of  the  Potsdam  fauna 
are  printed  in  italics):  Lingulepis  Mcera,  L.  minuta,  Lingula?  manticula, 
Discina  (sp.  undt.),  Acrotreta  gemma,  Schizambon  typicalis,  Obolella 
ambigua,  0.  discoidea,  Leptcena  Melita,  Orthis  Hamburgensis,  0.  testudi- 
naria,  Triplesia  calcifera,  Tellinomya  ?  Hamburgensis,  Agnostus  communis, 
A.  bidens,  A.  Neon,  Dicellocephalus  finalis,  D.  inexpectans,  Ptychoparia  ? 
annectans,  Ptychoparia  affinis,  P.  granulosus,  P.  Haguei,  P.  Oweni,  P.  unisul- 
catus,  Arethusina  Americana,  Amphion  (sp.  undt.),  Barrandia  McCoyi,  Illse- 
nurus  Eurekensis,  Asaphus  Caribouensis. 

In  the  next  superior  grouping,  about  midway  of  the  Pogonip  Group, 
all  the  middle  Cambrian  genera,  with  the  exception  of  Orthis  and  Illgenurus, 
have  disappeared,  and  higher  up  the  genera  Receptaculites,  Chaetetes, 
Pleurotomaria,  Maclurea,  Cyphaspis,  Bathyurus,  and  Asaphus  carry  the 
fauna  up  to  the  summit  of  the  formation  where  the  genera  Receptaculites, 
Ptilodictya,  Chsetetes,  Strophomena,  Orthis,  Tellinomya,  Modiolopsis,  Ma- 
clurea, Cyrtolites,  Orthoceras,  Endoceras,  Coleoprion,  Leperditia,  Beyrichia, 
Amphion,  Ceraurus,  and  Asaphus  give  it  a  facies  approaching  that  of  the 


4  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Lower  Trenton  and  indicating  an  horizon  that  is  considered  to  be  in  a 
measure  the  equivalent  of  that  of  the  Chazy  formation  of  New  York  and 
Canada.  The  fauna  of  the  lower  portion  of  the  Pogonip  Group  corre- 
sponds in  the  same  manner  to  that  of  the  Calciferous  sand-rock  of  the  same 
region.  The  large  number  of  individuals  of  the  species  of  Receptaculites, 
E.  mammillaris  especially,  gives  the  fauna  of  the  upper  beds  a  character 
that  this  horizon  has  not  hitherto  had.  This,  united  with  several  of  the 
Trenton  species,  viz,  Orthis  testudinaria,  0.  tricenaria,  0.  perveta,  Tellinomya 
contracta,  two  species  of  Modiolopsis  allied  to  Trenton  forms,  and  Eaphis- 
toma  Nasoni,  strongly  foreshadows  the  opening  of  the  Trenton  period. 

The  fauna  between  that  of  the  Pogonip  and  the  Devonian  horizon  is 
so  meager  that  the  only  reference  made  to  it  is  in  the  systematic  list  and  in 
the  lists  of  the  geologic  report  (Geology  of  the  Eureka  District).  As  the 
determination  of  a  higher  Silurian  horizon  than  that  of  the  Trenton-like 
fauna  in  the  limestone  above  the  quartzite  capping  the  Pogonip  Group 
rested  mainly  on  the  presence  of  the  genus  Halysites,  the  opinion  of  Prof. 
James  Hall  was  requested  as  to  the  generic  relations  of  the  specimens  that 
had  been  referred  to  Halysites  in  the  field.  While  he  did  not  say  positively 
that  the  form  represented  was  Halysites,  he  expressed  the  opinion  that  it 
was  of  organic  origin,  and  that  he  knew  of  nothing  else  but  Halysites  to 
which  it  could  be  referred.  This  conclusion  has  since  been  fully  proven  by 
the  discovery  of  fine  specimens  of  Halysites  catenulatus  at  the  same  horizon 
in  the  White  Pine  District,  Nevada,  associated  with  specimens  in  a  similar 
state  of  preservation  as  those  from  Lone  Mountain. 

The  fauna  of  the  Devonian  is  large  and  representative,  notwithstand- 
ing some  species  have  reversed  their  relative  position  in  the  group  as  they 
have  been  known  heretofore,  and  others  have  a  greater  vertical  range. 
Among  the  brachiopods,  Orthis  Tulliensis,  of  the  Tully  limestone  of  New 
York  State,  is  found  at  the  summit  of  the  Devonian  limestone,  and  Orthis 
impressa,  a  Chemung  species  of  New  York,  at  the  base,  associated  with 
eastern  Upper  Helderberg  limestone  species;  and  a  variety  of  Atrypa  reti- 
cularis,  characteristic  of  the  Niagara  limestone,  and  unknown  heretofore 
elsewhere,  occurs  with  the  former  in  the  upper  beds.  Among  the  corals, 
Cladopora  pulchra,  Syrmgopora  Hisingeri,  and  Cyaihophyllum  corniculum,  of 


SUMMAR1   OF  RESULTS. 

the  great  Corniferous  coral  reef  of  the  east,  occur  at  the  upper  horizon,  and 
Syringopora  perelegans,  of  the  same  formation  in  New  York,  ranges  through- 
out the  group  in  Nevada.  The  occurrence  of  rare  species  and  those  of 
limited  range  in  the  eastern  Devonian  is  not  an  unusual  feature,  as  we 
find  Lingula  Lcena,  Strophodonta  Patersoni,  Chonetes  hemispkerica,  Productus 
truncatus,  etc.  The  Trilobita  also  show  the  great  range  of  the  two  species 
heretofore  regarded  as  restricted  to  certain  localities,  viz,  Proetus  Halde- 
mani  and  P.  marginalia,  and  also  the  more  widely  distributed  Phacops  rana. 
Among  species  of  a  greater  range  there  is  the  well-known  Pterinea  flabdla 
in  association  with  other  forms  of  the  Upper  Helderberg  formation  at  the 
Lower  Devonian  horizon;  and  Sanguinolites  rigidus  and  8.  ventricosus,  of  the 
Chemung  Group,  occur  in  the  upper  beds  of  limestone.  The  Gasteropoda 
are  shown  by  Platyostoma  lineatum,  so  abundant  in  the  Hamilton  formation 
of  New  York,  and  eight  species  of  Platyceras,  five  of  which  are  identical 
with  eastern  species,  as  are  the  four  species  of  Tentaculites  and  the  minute 
Styliola  fissurella  representing  the  Pteropoda. 

The  fortunate  discovery  of  the  interior  of  a  dorsal  valve  of  a  rather 
large  species  of  Lingula,  L.  Whitei,  affords  the  means  of  comparison  of  the 
same  parts  of  the  shell  with  a  Silurian  and  recent  species  of  this  genus,  and 
proves  the  great  structural  similarity  of  the  three  species  so  widely  sepa- 
rated in  geologic  time  (Plate  xxi,  figs.  18,  19,  20). 

The  fauna  of  the  White  Pine  shale  in  the  White  Pine  District  is  in 
many  respects  a  peculiar  one,  combining  as  it  does  species  ranging  from  the 
Middle  Devonian  into  the  Lower  Carboniferous.  The  stratigraphic  position 
of  the  shale  is  at  the  summit  of  the  Devonian  system  and  at  the  base  of 
the  Carboniferous;  it  is  overlain  in  the  Eureka  District,  where  the  section  is 
unbroken,  by  a  massive  belt  of  conglomerate  before  the  limestones  carrying 
the  Lower  Carboniferous  fauna  appear  in  the  section.  The  strongly- 
marked  Carboniferous  species  are,  Spiriferina  cristata,  Retzia  radialis,  Athyris 
suUamellosa,  and  Cardiomorpha  Missouriensis ;  these  are  associated,  at  the 
same  horizon,  with  such  Devonian  species  as  Distinct,  Lodensis,  Productus 
subaculeatus,  Ambocoelia  umbonata,  RTiynchonella(L.} quadricostata,  Aviculopecten 
catactus,  and  Lunulicardium  fragosum. 

Messrs.  Hall  and  Whitfield  (Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  201) 


6 


PALEONTOLOGY  OF  THE  EUBEKA  DISTRICT. 


considered  Cardiomorpha  Missouriensis  and  fragments  of  a  Spirifera  of  the 
type  of  Spirifera  Rockymontana  Marcou  (— £  KeokuJc  Hall),  as  probably 
indicating  a  division  of  the  black  shales  into  Carboniferous  and  Devonian, 
but,  from  field  observations  and  the  assemblage  of  fossils,  such  a  division 
is  incompatible  with  the  facts.  The  White  Pine  shales  occupy  the  same 
position  with  relation  to  the  Devonian  and  the  Carboniferous  systems  as 
does  the  lower  portion  of  the  Pogonip  limestone  to  the  Cambrian  and  Silu- 
rian systems.  In  each  case  there  are  beds  of  passage  carrying  a  fauna  that 
unite  the  faunas  of  the  two  systems. 

That  the  Devonian  portion  of  the  White  Pine  shale  fauna  is  more 
nearly  related  to  that  of  the  shales  of  the  Hamilton  Group  than  that  of  the 
Chemung  horizon,  as  found  in  the  neighboring  Eureka  District,  is  owing 
undoubtedly  to  the  character  of'  the  environment  of  the  fauna  during  the 
deposition  of  the  shales,  a  feature  so  well  shown  in  the  recurrent  faunas  of 
the  Devonian  of  New  York  as  studied  by  Prof.  H.  S.  Williams. 

A  summary  of  the  Devonian  fauna  is  given  in  the  following  table: 


Clam. 

Nevada. 

Common  to  Nevada 
and— 

New  York. 

Falls 
of 
Ohio. 

Iowa. 

| 

1 
* 

Lower  Devonian. 

Upper  Devonian. 

Upper  and  Lower 
Devonian. 

Genera. 

1 

02 

00 

•S 
o 

1 

i 

I 

Porif  era  

3 
14 
2 
26 
29 
13 
5 
4 
2 
4 

3 

27 
3 
*83 
42 
39 
8 
11 
2 
7 

3 

15 
3 
50 
27 
23 
7 
7 
2 
4 

1 
13 

1 

1 

2 
11 
2 

Actinozoa  ................. 

11 

9 

9 

1 
11 
2 

Polyzoa  

BracMopoda  

51 
17 
17 
2 
4 

18 
2 
1 

1 

26 
27 
11 
5 
4 

38 
9 
12 
5 

8 
2 
4 

Lamellibranchiata  

Gasteropoda  

Pteropoda  

Cephalopoda  

Crustacea  

2 

Pcecilopoda  

3 



4 

4 

Total  

102 

225 

141 

108 

24 

94 

79 

23 

17 

*  And  five  varieties. 


Of  the  two  hundred  and  twenty-five  species,  sixty-one  are  described 
for  the  first  time,  forty-five  species  are  referred  to  genera  but  not  specifi- 


SUMMARY  OF  RESULTS. 

cally  named,  and  one  hundred  and  nineteen  species  are  identified  with 
species  already  known ;  of  the  latter,  seventy-nine  are  identical  with  species 
found  in  New  York  State;  eleven  species  occur  in  Iowa  that  are  unknown 
in  New  York,  and  the  remaining  species  occur  in  various  localities  both  in 
the  Rocky  Mountains  and  the  central  and  eastern  portions  of  the  continent. 
The  stratigraphic  position  of  each  species  is  given  in  the  systematic  list  at 
the  close  of  the  descriptions 

The  Upper  Helderberg  horizon  of  the  New  York  series  is  represented 
by  thirty-eight  species  common  to  it  and  the  lower  portion  of  the  Devonian 
of  the  Eureka  District;  the  Chemung  Group  of  the  same  by  sixteen 
species;  of  the  Hamilton  species  of  New  York,  twenty-three  are  distributed 
through  the  lower  portion  of  the  Eureka  Devonian  limestone  and  eighteen 
species  in  the  middle  and  upper  portions,  but  not  in  such  a  manner  as  to 
distinguish  a  middle  division  corresponding  to  the  Hamilton  formation  of 
New  York.  Of  strictly  Hamilton  species  in  New  York,  twenty- three  are 
found,  of  which  eleven  are  in  beds  a  little  below  the  summit,  and  twelve 
just  above  the  base  of  the  formation. 

Of  ichthyic  remains  there  is  but  one  Ctenacanthus-like  tooth.  This  with 
a  single  tooth  of  the  genus  Cladodus,  brought  from  near  the  Hot  Springs 
of  Humboldt  Canon,  by  the  geologists  of  the  Fortieth  Parallel  Survey,  is 
all  that  is  known  of  this  fauna  in  Central  Nevada,  although  from  the  pres- 
ence of  a  strongly-marked  horizon  of  Devonian  fishes  in  the  Kanab  Canon 
of  Northern  Arizona,  it  is  a  little  remarkable  that  so  few  specimens  have 
been  discovered  to  the  north,  where  the  formation  has  a  much  greater  devel- 
opment. 

With  the  exception  of  a  species  of  Psilophyton,  a  fragment  of  Cordaites, 
and  a  few  obscure  fucoidal  remains,  the  flora  of  the  period  is  unrepresented, 
although  in  the  upper  beds  the  conditions  necessary  for  the  preservation  of 
vegetable  remains  appear  to  have  been  favorable. 

The  Devonian  corals  as  well  as  those  of  the  Silurian  and  Carbonifer- 
ous are  not  illustrated,  and  only  short  notes  are  given  of  a  portion  of  the 
twenty-seven  species  occurring  in  the  Devonian.  From  what  is  already 
known  of  this  portion  of  the  fauna,  there  is  little  doubt  but  that  future  col- 
lections from  the  area  of  the  Great  Basin  will  give  a  very  complete  series 


8  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

of  species,  and  still  further  increase  the  number  of  species  common  to  the 
eastern  and  central  (or  Atlantic  and  Mississippi)  areas  and  the  western  or 
Rocky  Mountain  area. 

The  fauna  of  the  Upper  Carboniferous  limestone  is  composed  of  old  and 
well-known  species  usually  occurring  at  that  horizon,  and  gives  but  three 
species  new  to  the  region  of  the  Rocky  Mountains,  viz,  Ptikdictya  carbonaria, 
P.  serrata,  and  Macrodon  tenuistriata.  The  comparatively  few  species  occur- 
ring in  the  middle  and  upper  portions  of  the  Lower  Carboniferous  Group 
are  also  well-known  forms,  but  at  the  lower  horizon  we  meet  with  a  most 
interesting  assemblage  of  species.  It  embraces  a  large  number  of  Lamelli- 
branchiate  shells,  a  class  so  rarely  represented  in  collections  from  this 
region,  and  unites  the  characters  of  the  fauna  of  the  Lower  Carboniferous 
groups  of  the  Mississippi  Valley  with  that  of  the  Coal-Measures  in  a  remark- 
able degree,  a  feature  not  uncommon  in  the  Lower  Carboniferous  of  the 
Rocky  Mountains,  but  rarely  so  well  shown  as  in  the  Eureka  District. 

There  is  also  a  certain  commingling  of  Upper  Devonian  species  with 
the  Lower  Carboniferous  fauna.  We  find  Discina  Newberryi,  Macrodon 
Hamiltonce,  Grammysia  Hannibalensis,  G.  arcuata,  Sanguinolites  JEolus,  and 
Pleurotomaria  nodomarginata  associated  with  common  Carboniferous  species. 

The  discovery  of  Pulmoniferous  mollusks  of  the  genera  Physa  and 
Zaptychius  in  association  with  the  fresh-water  shell  AmpuUaria^  Powelli  and 
fragments  of  a  flora,  coniferous  in  character,  supports  the  stratigraphic 
evidence  of  the  presence  of  a  near  or  not  distant  land  area  at  the  time  of 
the  deposition  of  the  Lower  Carboniferous  rocks  of  Central  Nevada.  It 
also  gives  the  first  notice  of  the  occurrence  of  the  Pulmonifera  in  rocks  of 
this  age;  the  land  shells  of  Nova  Scotia  and  Illinois  occur  in  the  Coal- 
Measures,  and  Strophites  grandceva,  Dawson,  is  from  the  Devonian  plant 
beds  of  New  Brunswick.  The  bearing  of  this  discovery  on  the  question 
of  the  presence  of  land  areas  from  the  time  of  the  Middle  Paleozoic  to  the 
present  is  important,  No  other  explanation  offers  than  that  there  was  a  con- 
tinuous fresh-water  habitat,  ponds  or  streams,  which  permitted  the  genera 
to  descend  in  a  direct  line  from  Paleozoic  time  to  the  present. 

The  grouping  of  the  genera  and  species  in  the  strata  is  shown  in  a 
general  manner  in  the  systematic  list  at  the  end  of  this  volume,  and  in 


SUMMAKY  OF  EESULTS. 


9 


greater  detail  in  the  abstract  of  a  report  on  the  geology  of  the  Eureka 
District,  Nevada,  by  Mr.  Arnold  Hague,  contained  in  the  Third  Annual  Re- 
port of  the  Director  of  the  United  States  Geological  Survey. 

In  the  accompanying  table  the  number  of  genera  and  species  known 
at  present  in  the  Paleozoic  formations  of  Central  Nevada  is  given: 


1 

B 

- 

Geologic  horizons. 

.s| 

CD 

a 

I 

& 

3* 

"5  P. 

§ 

*« 

p 

j 

! 

a  « 

P. 

2 

© 

i 

Q 

| 

te 

a 

§ 

£ 

E 

a 

cb 

02 

A 

fe 

t> 

« 

Cambrian  

24 

69 

32 

31 

6 

Silurian: 

47 

99 

84 

31 

34 

15 

Trenton,  etc  

14 

15 

4 

11 

Devonian   

102 

225 

119 

61 

45 

Carboniferous 

65 

132 

53 

50 

29 

8 

Total  

252 

540 

242 

173 

125 

18 

Recurrent  

8 

18 

18 

Total  

244 

522 

224 

173 

125 

FOSSILS    OF    THE    C  A.  M  B  H  I  A.  1ST . 

PROSPECT   MOUNTAIN   GROUP. 

PORIFERA. 
Genus  PROTOSPONGIA  Salter. 

Protospongia  fenestrata  Salter. 
Plate  ix,  figs.  5,  5  a,  b. 

Protospongia  fenestrata  Salter,  1864.    Quart.  Jour.  Geol.  Soc.,  vol.  xx,  p.  238,  pi.  13, 

fij?.  12  a,  6.    Ibid.,  Cat.  Cambrian  and  Silurian  Fossils,  p. 

3, 1873. 
Hicks,  1874.     Quart.  Jour.  Geol.  Soc.,  vol.  xxvii,  p.  401,  pi. 

1(1,  fig.  20. 
Zittel,  1877.    Abh.  dor  K.  bayer.  Akademie  der  Wiss.    2  CL, 

xiii ;  Bd.  "  Studien  ii,  fossile  Spongien"  (p.  45,  sep.  copy). 
Carter,  1877.    Ann.  and  Mag.  Nat.  Hist.,  ser.  4,  vol.  xxv,  p.  177. 
Brogger,  1878.    On  paradoxidesskifrene  ved  Krekling.    Sep- 

arataftryk  af  Nyt  Magazin  for  Naturvidensk.  vol.  xxiv,  i,  p. 

20,  t.  6,  f.  14. 
Sollas,  1880.    Quart.  Jour.  Geol.  Soc.,  vol.  xxxvi,  p.  362,  figs. 

1,2. 

Koemer,  1880.    Leth.  Geogn.,  1  Th.  p.  316,  f.  59. 
Hinde,  1883.    Cat.  Fossil  Sponges,  p.  129,  pi.  xxviii.  fig.  2. 

Mr.  Salter  originally  described  this  interesting  sponge  as  having  a 
loosely  reticulate  skeleton  formed  of  very  large  cruciform  spiculse,  the 
branches  of  which  cross  each  other  at  an  angle  of  80°,  and  only  in  one 
plane,  no  ascending  or  descending  branches  rising  from  the  point  of  con- 
junction. The  angles  occasionally  vary,  but  not  much. 

More  perfect  specimens  obtained  by  Dr.  Hicks  show  the  spiculse  to  be 
quadriradiate,  slightly  raised  at  the  center  and  formed  of  four  nearly  cylin- 
drical rays. 

The  skeleton,  as  described  by  Mr.  Sollas,  is  composed  of  large  primary 

spiculse  with  the   interspaces  filled  in  by  three  series  of  spiculse,  each 

11 


12  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

formed  of  spiculse  smaller  than  those  preceding  it,  their  rays  all  lying 
regularly  disposed  in  two  directions  at  right  angle  to  each  other,  and  so 
building  up  a  net-work  with  square  meshes. 

The  skeleton  is  not  preserved  in  any  of  the  Nevada  specimens,  the 
different  sized  spiculse  lying  scattered  on  the  surface  of  the  limestone  shale 
or  crowded  together  without  any  regularity  to  the  direction  of  the  rays  or 
the  size  of  the  spiculse.  The  spiculse,  however,  appear  to  be  identical  in 
all  respects  with  those  described  by  Messrs.  Salter,  Hicks,  and  Sollas,  and 
if  they  had  not  been  scattered  or  crowded  together  by  accident  would 
form  a  skeleton  similar  to  that  described  by  Mr.  Sollas.  The  under  side  of 
the  spiculse  show  no  trace  of  a  fifth  ray  or  its  point  of  attachment,  appearing 
in  this  respect  like  the  upper  side,  except  that  the  surface  is  a  little  concave 
instead  of  convex  as  on  the  upper  side.  They  are  silicious,  and  differ  in 
mineral  character  from  the  spiculse  from  the  Cambrian  rocks  of  Wales 
which  have  been  replaced  by  pyrite. 

Dr.  Hicks  states  that  P.  fenestrata  occurs  in  the  Longmynd  Group, 
in  the  Menevian  Group,  and  also  in  the  Upper  Lingula  flags  to  the  base  of 
the  Tremadoc  rocks,  giving  a  vertical  range  of  from  8,000  to  10,000 
feet  (Quart.  Jour.  Geol.  Soc.  London,  vol.  xviii,  p.  181.  1872).  It  also 
occurs  in  black  shales  of  Cambrian  age  in  Norway  and  Sweden. 

Formation  and  localities. — Cambrian,  Prospect  Mountain  Group.  In 
the  mountain  shale  near  the,  Eldorado  mine,  and  in  the  Secret  Caflon  shale 
on  the  east  side  of  Secret  Canon,  Eureka  District,  Nevada. 


BRACHIOPODA. 
Genus  LINGULEPIS  Hall. 

Lingulepis  Maera  PI.  &  W. 

Lingulepis  Mcera  Hall  &  Whitfield,  1877.    Geol.  Expl.  Fortieth  Parallel,  vol.  iv,  p. 
206,  pi.  i,  figs.  5-7. 

The  specimens  referred  to  this  species  are  specifically  identical  with 
the  types  collected  by  the  geologists  of  the  Fortieth  Parallel  Survey  in  the 
Eureka  District. 


FOSSILS  OF  THE  (JAMBEIAN. 


13 


The  species  is  well  represented,  and  appears  to  be  characteristic  of  the 
Upper  portion  of  the  Cambrian  and  the  lower  horizon  of  the  Silurian, 
Pogonip  Group.  It  occurs  in  the  Secret  Canon  shale  of  the  Cambrian  on  the 
eastern  side  of  the  canon  directly  east  of  Ruby  Hill;  in  the  limestone  of 
the  Pogonip  Group  northeast  of  Adams  Hill;  on  the  ridge  southeast  of  the 
Jackson  mine;  on  the  southwest  spur  of  Wpod  Cone,  and  southeast  of  the 
Hamburg  mine,  Eureka  District,  Nevada. 


Lingulepis  f  minuta  H.  &  W. 

Lingulepis  f  minuta  Hall  &  Whitfield,  1877.    Geol.  Expl.,  Fortieth  Parallel,  vol.  iv, 
p.  206,  pi.  i,  figs.  3,  4. 

This  species  has  nearly  the  same  vertical  range  and  geographical 
distribution  as  Lingulepis  Mcera,  usually  occurring  in  the  same  localities. 
The  type  specimens  were  obtained  in  the  Eureka  District  by  the  members 
of  the  Fortieth  Parallel  Geological  Survey. 


Genus  LINGULA  Bruguiere. 

Lingula  f  manticula  White. 

Plates  is,  fig  3,  and  xi,  fig.  2. 

Lingula  1  manticula  White,  1874.    Expl.   and  Surv.  West  100th  Merid.j    Prelim. 
Eep.  Pal.,  p.  9.    Ibid.,  vol.  iv,  pt.  1,  p.  52,  pi.  iii,  figs.  2«,  6,  1875. 

The  range  of  variation  among  the  specimens  we  have  referred  to  this 
species  is  greater  than  exists  between  them  and  our  conception  of  L.  f 
manticula,  as  obtained  from  the  description  and  illustrations  given  by 
Dr.  White,  and  without  a  direct  comparison  with  the  type  specimens  to 
determine  any  specific  differences,  if  they  exist,  we  consider  them  as  one 
species.  As  none  of  the  examples  show  the  internal  characters  of  the  shell, 
the  doubtful  character  of  the  generic  reference  remains  unchanged. 

The  type  specimens  were  collected  in  the  Schell  Creek  Range  of  Ne- 
vada, at  an  horizon  in  the  Silurian,  equivalent  probably,  to  the  horizon  at 
which  the  species  occurs  in  the  Pogonip  Group. 


14  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Formation  and  localities. — Cambrian,  Prospect  Mountain  limestone, 
just  beneath  the  Secret  Canon  shale,  in  the  700-foot  level  of  the  Richmond 
mine,  Ruby  Hill ;  at  the  summit  of  the  Secret  Canon  shale  in  New  York 
Canon;  also  in  the  lowest  portion  of  the  Pogonip  limestone  northeast  of 
Adams  Hill  and  higher  up  in  the  same  group  on  the  eastern  slope  of  the 
ridge  east  of  the  Hamburg  Ridge,  Eureka  District,  Nevada. 


Genus  OBOLELLA  Billings. 
Obolella  discoidea  H.  &  W. 

Obolella  discoidea,  Hall  &  Whitfield,  1877.    Geol.  Expl.  Fortieth  Parallel,  vol.  iv,  p.  205, 
pi.  i,  figs.  1,  2. 

This  is  one  of  the  species  brought  in  by  the  geologists  of  the  Fortieth 
Parallel  Survey  from  the  Eureka  District.  It  occurs  in  the  Hamburg 
shale  of  the  Cambrian,  and  the  Pogonip  Group  of  the  Silurian,  on  the 
ridge  east  of  the  Hamburg  Ridge  and  at  the  Pogonip  horizon  in  the  lime- 
stone northeast  oi?  Adams  Hill ;  also  on  the  first  ridge  southeast  of  the  Jack- 
son mine,  Eureka  District,  Nevada;  and  in  the  Pogonip  limestone  on  Pogo- 
nip Ridge,  White  Pine  District,  Nevada. 

Genus  ACROTHELE  Linnarsson. 

Acrotbele  ?  dichotoma,  n.  sp. 

Plate  ix,  fig.  11. 
/ 

Shell  of  medium  size,  thin,  corneous,  nearly  circular  in  outline,  the 
transverse  diameter  being  a  little  greater  than  the  longitudinal. 

Ventral  valve  depressed,  discoid,  with  the  apex  but  slightly  elevated 
above  the  general  plane  of  the  surface  and  situated  about  one-third  the 
distance  from  the  posterior  to  the  anterior  margin.  The  apex  is  perforate 
and  has  a  narrow  groove  around  it,  except  on  the  posterior  side,  where  a  low 
rim  alone  separates  the  groove  and  the  slightly-depressed  pseudo-deltidial 
area.  This  area  is  triangular  in  form,  and  extends  to  the  posterior  margin, 
gradually  expanding  to  a  width  a  little  less  than  its  length ;  it  appears  to 
have  been  quite  minute  at  first  just  beneath  the  apex  and  to  have  been  filled 


FOSSILS  OF  THE  CAMBRIAN. 


15 


in  by  successive  additions  of  the  shell,  so  that  the  general  circular  outline 
of  the  shell  has  scarcely  been  broken  by  the  very  slight  truncation  of  the 
posterior  margin.  The  additions  to  the  posterior  margin  of  the  false  area 
are  crowded  together  as  little  transverse  ridges  with  fine  striae  between. 

The  outer  portion  of  the  shell  is  largely  exfoliated,  but  traces  of  ra- 
diating striae  and  concentric  lines  of  growth  are  shown.  The  latter  on  the 
outer  portion  appear  to  have  been  continuous  with  those  crossing  the 
pseudo-deltidial  area  From  each  side  of  the  apex  a  narrow,  elongate, 
muscular  scar  gently  diverges,  extending  towards  the  central  portion  of  the 
shell.  Transverse  diameter,  7.5mm;  longitudinal  diameter,  6.75mm;  eleva- 
tion or  convexity,  about  0.75mm. 

The  reference  of  this  species  to  the  genus  Acrothele  is  made  with  reser- 
vation. Its  depressed  form  and  eccentrically-perforated  apex  are  similar, 
while  the  false  area  and  the  muscular  scar  are  different.  It  is,  however, 
more  closely  allied  to  Acrothele  than  with  any  genus  with  which  we  are 
acquainted. 

Formation  and  locality. — Cambrian,  Prospect  Mountain  Group;  upper 
beds  of  the  Secret  Canon  shale,  on  the  east  side  of  Secret  Canon,  Eureka 
District,  Nevada. 


Genus  SCENELLA  Billings. 

Scenella  ?  conula,  n.  sp. 
Plate  ix,  fig.  6. 

Shell  small,  conical ;  apex  subcentral,  apparently  with  a  tendency  to  bend 
a  little  to  one  of  the  sides  on  which  there  is  a  very  faintly-indicated  line  run- 
ning from  the  apex  to  the  margin.  Aperture  ovate.  Surface  smooth  to 
the  unaided  eye;  it  shows  fine  concentric  striae  and  a  few  obscure  lines  of 
growth  when  examined  by  the  aid  of  a  strong  magnifying  glass. 

Dimensions. — Greater  diameter,  3mm;  lesser  diameter,  2.25mm;  eleva- 
tion, about  1.75mm. 

This  is  a  small  Metoptoma-like  shell,  the  generic  reference  of  which  is 
provisional,  as  it  differs  from, the  type  of  the  genus,  Scenella  reticulata,  in  not 
having  a  carina  running  from  the  apex  to  the  margin;  the  curvature  of 


16  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

the  apex  is  not  positively  known,  as  its  summit  is  broken  off  in  all  the 
specimens  in  the  collection. 

The  line  from  the  apex  to  the  margin  is  too  strongly  represented  in  the 
figure  on  plate  ix. 

Formation  and  locality. — Cambrian,  Prospect  Mountain  Group;  low 
down  in  the  massive  limestone  beneath  the  Secret  Cafion  shale  on  the  east 
slope  of  Prospect  Mountain,  Eureka  District,  Nevada. 


Genus  ACEOTEETA  Kutorga. 

Mr.  Davidson,  in  his  Classification  of  the  British  Fossil  Brachiopoda, 
gives  an  accurate  generic  description  of  the  external  form  and  character  of 
the  valves  of  Acrotreta,  but  not  having  specimens  showing  the  interior  of 
the  valves,  he  left  the  genus  doubtfully  as  a  subgenus  of  Siphonotreta. 
The  fortunate  discovery  of  a  large  number  of  specimens  of  Acrotreta  gemma 
Billings,  in  the  passage-beds  between  the  Cambrian  and  Silurian  limestones 
of  the  Eureka  District,  affords  material  for  the  study  of  the  interior  char- 
acters of  the  smaller  valve,  and  also  some  of  those  of  the  larger  or  conical 
valve. 

The  interior  of  the  larger  valve  shows  a  perforated,  rounded,  nipple- 
like  projection  extending  down  from  the  apex,  plate  1 ,  fig.  If.  This  is  well 
shown  in  the  cast,  fig.  1  fe.  On  each  side  a  slight  ridge  extends  obliquely 
forward.  No  other  markings  can  be  determined.  In  the  smaller  valve  a 
strong  median  ridge  extends  from  in  front  of  a  minute  triangular  space  on 
the  cardinal  margin  two-thirds  the  distance  to  the  front  margin  of  the  shell. 
Just  back  of  the  center  of  the  shell  a  small  oval  scar  occurs  on  each  side  of 
the  ridge,  and  near  the  cardinal  margin  another  pair  of  larger  crescentiform 
scars.  A  pair  of  lateral  marginal  scars  are  very  faintly  shown  on  two  ex- 
amples. They  are  usually  too  indistinct  to  be  recognized. 

Comparing  this  interior  with  that  of  the  smaller  valve  of  Siphonotreta 
unguiculata,  as  illustrated  by  Davidson  (Geol.  Mag.  N.  S.,  vol.  iv,  pi.  ii, 
fig.  II,  1877),  the  differences  between  them  are  well  marked,  especially 
in  the  greater  spreading  out  of  the  muscular  impressions  in  Acrotreta. 


FOSSILS  OF  THE  CAMBEIAN. 


17 


In  the  larger  valves  the  conical  form  and  siphonal  tube  strongly  relate  them. 
(See  plate  i,  figs.  1 6,  I/,  and  fig.  8.) 

The  interior  of  the  smaller  valve  shows  a  wonderful  similarity  to  that 
of  Obolella  f  ficabrince  Callaway  (Dav.  Mon.  Brit.  Foss.  Brach.,  vol.  v,  pt.  ii, 
p.  211,  pi.  xvi,  fig.  2 7  d\  (see  plate  1,  fig.  lc,)  and  I  can  hardly  understand 
that  they  belong  to  separate  genera.  If  the  conical  valve  of  0.  f  Scabrina 
should  be  found  to  show  indications  of  a  perforate  apex,  the  relations  of  the 
species  to  Acrotreta  gemma  would  be  very  close. 


Acrotreta  gemma  Billings. 
Plate  i,  figs,  la,  If,  Id-/;  plate  ix,  figs.  9,  9 a. 

Acrotreta  gemma  Billings,  1865.    Palaeozoic  Fossils,  vol.  i,  p.  216,  figs.  201  a,/. 
Acrotreta  subconica  and  A.  attenuata  Meek,  1873.    Sixth  Ann.  Eep.  TJ.  S.  Geol.  Surv. 

Terr.,  p.  463. 
Acrotreta  pyxidicula  White,  1874.    Expl.  and  Surv.  West  100th  Merid.,  Eep.  Invert, 

Foss.,  p.  9.    Ibid.,  vol.  iv,  p.  53,  pi.  iii,  figs.  3  o-d,  1875. 

The  specific  identity  of  the  forms  from  Nevada  with  those  from  New- 
foundland scarcely  permits  of  question  if  based  on  the  description  and  illus- 
trations given  by  Mr.  Billings.  Some  specimens  have  the  conical  valve 
more  or  less  elevated,  but  the  difference  is  not  of  specific  value. 

Dimensions  of  an  average  specimen:  height  of  conical  valve,  l.TS111™; 
transverse  diameter,  2mm;  longitudinal  diameter,  1.75mm. 

The  species  from  the  passage  beds  between  the  Cambrian  and  Silurian 
faunas  on  the  Gallatin  River,  Montana,  doubtfully  identified  by  Mr.  Meek 
as  A.  subconica  Kutorga,  and  in  case  of  eventually  proving  to  be  a  distinct 
species  to  be  called  A.  attenuata,  proves  on  comparison  to  be  the  same  as  the 
Eureka  species,  and  it  is  also  associated  with  Iphidea  sculptilis,  Agnostus  bidens, 
and  Ptychoparia  Oweni,  at  each  locality.  The  mesial  furrow  on  the  false 
area  is  a  variable  character,  as  also  within  somewhat  broad  limits  the  depres- 
sion or  elevation  of  the  conical  valve.  With  the  specimens  before  me  for 
comparison,  they  are  all  referred  to  the  one  species  and  identified  with  A. 
gemma.  Acrotreta  pyxidicula  White,  from  Nevada,  occurs  at  about  the  same 
geologic  horizon.  The  smaller  valve  is  identical  with  that  of  A.  gemma; 
2  o  D  w 


18  PALEONTOLOGY  OF  THE  EUREKA  DISTEICT. 

the  larger  is  greatly  depressed,  but  there  are  examples  uniting  it  with  the 
more  elevated  valve  of  A.  gemma. 

Formation  and  localities. — Cambrian  and  Silurian.  At  the  summit  of  the 
Secret  Canon  shale  in  New  York,  and  Secret  Canons,  and  opposite  the  dump 
of  the  Eichmond  mine  shaft,  Ruby  Hill ;  it  also  passes  up  through  the  shaly 
beds  capping  the  massive  Hamburg  limestone  belt  into  the  beds  of  the 
Pogonip  Group,  on  the  ridge  opposite  the  Hamburg  mine;  at  about  the 
same  horizon  northeast  of  Adams  Hill,  and  on  the  ridge  southeast  of  the 
Jackson  mine,  Eureka  District,  Nevada,  The  species  was  found  in  1882 
on  I^ogonip  Ridge,  White  Pine  District,  Nevada. 


Genus  KUTORGINA  Billings. 

Kutorgina  Whitfieldi,  n.  sp. 
Plate  ix,  figs.  4,  4  a. 

Shell  convex,  hinge  line  straight  and  a  little  less  than  the  greatest 
width  of  the  shell,  sides  rounding  regularly  into  the  slightly  convex  frontal 
margin. 

Ventral  valve  quite  convex,  elevated  along  the  center  to  form  a  flat 
depressed  fold,  and  sloping  quite  rapidly  from  this  to  the  lateral  and  cardinal 
margins;  median  elevation  with  about  five  rather  faintly-defined,  simple 
plications  that  reach  up  to  the  higher  portion  of  the  valve;  beak  small,  a 
little  depressed,  and  rising  above  the  area;  cardinal  margins  straight  and 
diverging  from  the  beak  at  an  obtuse  angle ;  character  of  area  unknown. 

Dorsal  valve  depressed  convex,  with  a  rather  wide,  shallow,  median 
depression,  and  two  short  plications  on  each  side  of  it  towards  the  front, 
which  are  obsolete  in  some  of  the  specimens;  the  area  between  the  cardinal 
edges  and  the  elevation  of  the  sides  of  the  mesial  depression  is  depressed  and 
corresponds  to  the  flattened  lateral  slope  of  the  ventral  valve. 

Surface  marked  by  fine,  very  clearly  defined  concentric  striae  subpar- 
allel  to  the  front  and  lateral  margins.  The  striae  are  crowded  together  into 
narrow  ridges,  giving  the  appearance  mentioned  by  Mr.  Billings  as  occur- 
ring on  the  type  species  of  the  genus. 


FOSSILS  OF  THE  CAMBRIAN. 


19 


This  species  is  unlike  any  described  that  is  known  to  me.  In  general 
form  and  surface  characters  it  is  allied  to  Kutorgina  cingulata  Billings,  and  is 
undoubtedly  of  the  same  genus  if  the  shells  illustrated  by  figs.  8  and  10,  on 
page  8,  of  the  "Paleozoic  Fossils  of  Canada,"  vol.  i,  are  taken  as  types. 
The  specific  name  is  given  in  honor  of  Prof.  R.  P.  Whitfield,  the  distin- 
guished paleontologist. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  beneath 
the  Secret  Cafion  shale,  on  the  west  side  of  Secret  Cation,  Eureka  District, 
Nevada. 


Kutorgina  Prospectensis,  n.  sp. 
Plate  ix,  figs,  la,  b. 

Shell  rather  small  for  a  species  of  the  genus.  It  is  thick  and  black,  like 
a  linguloid  shell. 

Ventral  valve  elevated,  with  the  apex  projecting  over  the  triangular 
area  and  extending  considerably  beyond  the  posterior  margin;  owing  to 
the  exfoliation  of  the  shell  the  extremity  of  the  apex  is  unknown ;  the  sur- 
face of  the  area  is  also  unknown.  Ventral  valve  depressed,  slightly  convex, 
without  a  mesial  sinus;  marginal  outline  subcircular,  with  the  posterior 
margin  obtusely  angular  at  the  beak;  the  beak  is  slightly  depressed  below 
the  highest  point  of  the  shell,  and  apparently  projects  a  trifle  beyond  the 
cardinal  edge.  Surface  marked  by  strongly-defined  fine  concentric  striae, 
ten  in  a  distance  of  one  millimeter,  where  they  terminate  on  the  posterior 
margin. 

The  dorsal  valve  of  this  species  is  much  like  that  of  Iphidea  Ldbrador- 
icus  Billings,  but  it  does  not  appear  to  come  within  the  limits  of  that  genus 
as  defined  by  the  type  species. 

Formation  and  locality. — Cambrian.  In  an  arenaceous  shale  resting  on 
the  Prospect  Mountain  quartzite,  summit  of  Prospect  Mountain,  Eureka 
District,  Nevada. 


20  PALEONTOLOGY  OF  THE  EUKEKA  DISTEICT. 

Kutorgina  sculptilis  Meek  (Sp). 
Plate  i,  figs.  7,  7  a,  6;  pi.  ix,  fig.  7. 

Iphidea  (f  f )  sculptilis  Meek,  1873.    Sixth  Ann.  Eep.  U.  S.  Geol.  Surv.  Terr,  for  the  year 

1872,  p.  479. 
Kutorgina  minutissima  Hall  &  Whitfield,  1877.     U.  S.  Geol.  Expl.  Fortieth  Par., 

vol.  iv,  p.  207,  pi.  i,  figs.  11,  12. 

Shell  minute,  semicircular  to  subquadrangular;  hinge  line  usually  a 
little  shorter  than  the  greatest  width  of  the  shell;  sides  slightly  rounded; 
antero-lateral  angles  rounded;  frontal  .margin  gently  convex  or  nearly 
straight  along  the  middle. 

Ventral  valve  obliquely  depressed,  subconical,  with  the  somewhat  ob- 
tusely pointed  apex  on,  or  slightly  extending  over,  the  cardinal  line;  area 
vertical  or  bending  a  little  backward,  triangular;  width  a  little  more  than 
twice  the  height,  but  not  as  broad  as  the  shell,  owing  to  the  sides  of  the  latter 
curving  in  to  meet  the  straight  area  at  an  angle  of  about  50° ;  foramen  (?) 
large,  dorsal  valve  depressed  convex,  most  elevated  on  the  umbo;  beak  a 
little  depressed,  scarcely  projecting  beyond  the  cardinal  line;  mesial  sinus 
faintly  defined,  not  much  more  than  a  slight  flattening  in  many  examples; 
area  low,  general  characters  unknown. 

Surface  of  the  shell  marked  by  very  fine,  sharp,  elevated,  concentric 
lines,  that  coalesce  or  bifurcate  irregularly,  giving  a  peculiar,  interrupted, 
wavy  appearance  under  the  magnifier;  these  lines  extend  around  on  the 
sides  of  the  posterior  side  or  area  to  the  edges  of  the  triangular  foraminal- 
like  opening.  Slightly  irregular,  slender,  depressed  or  elevated  interrupted 
lines  radiate  from  the  beak  or  apex;  they  vary  in  strength  and  number,  and 
on  some  shells  are  scarcely  discernible,  although  forming  a  prominent  feature 
in  many  individuals. 

Length  of  largest  shell  observed,  2.5mm ;  breadth,  3.75mm ;  depth  of  ven- 
tral valve,  1.25mm;  of  dorsal  valve,  0.5™*. 

The  type  of  Iphidea  (??)  sculptilis  (Meek)  is  a  strongly  marked  ventral 
valve  of  this  species  from  the  east  side  of  the  Gallatin  River,  Montana,  where 
it  is  associated  with  Acrotreta  gemma  Billings,  and  Ptychoparia  Oweni  Meek. 


FOSSILS  OF  THE  CAMBRIAN. 

In  the  Eureka  District  it  is  associated  with  the  same  species  at  the  same 
relative  geological  horizon.  I  now  have  before  me  Mr.  Meek's  type,  and 
also  the  type  of  Kutorgina  minutissima  H.  &  W.,  from  the  Eureka  District. 
They  evidently  belong  to  one  species  and  do  not  vary  from  each  other  more 
than  individuals  from  the  same  locality. 

The  generic  reference  of  the  species  by  Messrs.  Hall  and  Whitfield  is 
followed,  as  from  all  comparable  characters  the  species  is  closely  allied  to 
the  type  of  the  genus  Kutorgina  cingulata  Billings. 

As  yet  no  evidence  has  been  obtained  of  the  presence  of  a  pseudo-del- 
tidium  similar  to  that  in  Iphidea  lella  Billings.  Mr.  Meek  failed  to  detect  it 
in  working  away  the  matrix  from  the  specimens  he  used,  and  the  same  is 
the  case  with  the  material  from  the  Eureka  District.  From  the  fact  that 
the  pseudo-deltidium  is  often  absent  in  specimens  of  a  well-marked  species 
allied  to  /.  bella  now  before  me,  and  the  great  similarity  of  the  false 
area  of  the  larger  valves  of  it  and  K.  seulptilis,  when  in  that  condition,  I 
strongly  suspect  that  if  we  had  more  perfect  specimens  the  concentric  sur- 
face lines  would  not  stop  at  the  margin  of  the  triangular  space,  but  cross  a 
pseudo-deltidium,  as  in  I.  bella. 

As  stated  by  Mr.  Billings,  the  genera  Kutorgina  and  Iphidea  are  closely 
related  to  each  other,  and  while  it  is  convenient  to  have  the  two  genera  to 
refer  such  forms  as  K.  sculptilis  and  /.  betta,  with  our  present  knowledge  of 
the  two  genera,  Iphidea  cannot  be  considered  as  a  well-established  genus, 
although  it  is  quite  probable  that  if  we  had  the  interior  of  the  shell  of  each 
form  it  would  be  necessary  to  distinguish  them  as  Mr.  Billings  has  done. 

Formation  and  localities. — Upper  Cambrian.  Secret  Canon  shale  on  the 
east  side  of  Secret  Canon;  shaly  limestone  in  passage-beds  between  the 
Cambrian  and  Silurian  on  the  first  ridge  east  of  the  Hamburg  Mine,  Eureka 
District,  Nevada.  Also,  on  the  east  side  of  the  Gallatin  River  above  Gal- 
latin  City,  Montana,  as  labelled  in  the  collections  of  the  United  States  Na- 
tional Museum. 


22  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


Genus  LEPT^INA  Dalman. 
Leptaena  Melita  H.  &  W. 

Leptcena  Melita  Hall  &  Whitfield,  1877.    Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  208, 
pi.  i,  figs.  13,  14. 

This  species  is  given  by  its  authors  as  occurring  in  the  Lower  Silurian 
rocks  of  the  Eureka  District,  the  exact  horizon  being  unknown.  From  the 
examples  in  the  present  collection  we  learn  that  it  ranges  from  the  limestone 
beneath  the  Secret  Canon  shale  on  the  eastern  slope  of  Prospect  Mountain, 
up  through  the  intervening  strata  to  about  500  feet  above  the  base  of  the 
Pogonip  Group,  at  which  horizon  it  is  found  on  the  ridge  next  east  of  the 
Hamburg  Ridge;  also  southeast  of  the  Jackson  mine,  and  northeast  of 
Adams  Hill,  Eureka  District,  Nevada. 


Genus  ORTHIS  Dalman. 

Orthls  Eurekeiisis,  n.  sp. 
Plate  ix,  figs,  ti,  8  a. 

Shell  small,  transversely  suboval,  strongly  convex.  The  ventral  valve 
is  more  convex  than  the  dorsal,  and  elevated  along  the  middle  so  as  to  be- 
come subcarinate;  beak  small;  area  unknown. 

Dorsal  valve  convex,  with  a  strongly  marked  median  depression  that 
gives  it  a  bilobed  character;  beak  short  and  apparently  incurved  over  a 
low  area. 

Surface  marked  by  about  forty  strong,  simple,  radiating  striae  that 
extend  up  to  the  beak. 

Dimensions.  —  Transverse  diameter,  4mm;  length  of  ventral  valve,  S.b11"*  ; 
of  dorsal  valve,  3mm;  depth  of  ventral  valve,  1.5mm  ;  of  dorsal  valve,  about  lmm. 

From  the  nature  of  the  matrix  the  beaks  of  the  valves  are  usually 
broken  away  with  a  portion  of  the  shell  on  the  summit,  so  that  the  cast  of 
the  hinge-teeth  of  the  ventral  valve  and  the  muscular  impressions  of  the 
dorsal  valve  are  shown,  as  seen  in  fig.  8  a,  plate  ix. 

We  know  of  no  similar  form  from  this  horizon  with  which  to  compare 


FOSSILS  OF  THE  CAMBEIAN. 


23 


this  shell,  its  small  size,  bilobed  dorsal  valve,  and  subcarinate  ventral  valve 
distinguishing  it  from  all  other  described  species. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  at  the 
base  of  the  Secret  Canon  shale,  on  the  west  side  of  Secret  Canon,  Eureka 
District,  Nevada. 

PTEROPODA. 
Genus  STENOTHECA  Salter. 

Stenotheca  elougata,  n.  sp. 
Plato  ix,  figs.  2,  2 a. 

Shell  small,  elongate,  with  the  apex  incurved  and  depressed  nearly 
to  the  margin;  laterally  compressed  so  as  to  form  a  ridge  nearly  the 
entire  length.  Aperture  elongate,  ovate,  somewhat  acutely  pointed  at  the 
end  towards  which  the  apex  curves  and  rounded  at  the  opposite  extremity, 
the  greatest  width  occurring  about  two-thirds  the  distance  from  the  narrow 
end.  Surface  marked  by  numerous  fine  concentric  striae  and  lines  of 
growth. 

The  narrow  elongate  aperture,  depressed  apex,  and  fine  lines  of  growth 
serve  to  distinguish  this  from  described  species  of  the  genus.  As  far  as  yet 
known  the  genus  Stenotheca  is  confined  to  the  Cambrian  fauna. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  in 
the  limestone  just  beneath  the  Secret  Canon  shale,  on  the  west  side  of 
Secret  Canon,  Eureka  District,  Nevada. 


Genus  HYOLITHES  Eichwald. 
Hyolithes  primordialis  Hall  (Sp.) 

Theca  primordialis  Hall,   1861.    Eep.  Prog.    Geol.   Surv.  Wisconsin    (pam.),  p.  48. 

Ibid.,  Geol.  Wis.,  vol.  i,  p.  21,  fig.  5,  1862.    Ibid.,  Sixteenth  Eep.  N.  Y.  State 

Cab.  Nat.  Hist.,  p.  135,  pi.  vi,  figs.  30,  31,  1863. 
Hyolithes  (Theca)  primordialis  Hall  and  Whitfield,  1873.    Twenty-third  Eep.  N.  Y. 

State  Cab.  Nat.  Hist,  p.  242,  pi.  ii,  fig.  3. 
Hyolithes  primordialis  ?  White,  1874.    Expl.  and  Surv.  West  100th  Merid.,  Prelim.  Eep. 

Invert.  Foss.,  p.  6.    Ibid.,  vol.  iv,  pt.  1,  p.  37,  pi.  1,  figs.  5a~e,  1875. 
Hyolithes  primordialis  Whitfield,  1883.     Geol.  Wisconsin,  vol.  iv,  p.  175,  pi.  1,  fig.  12. 


24  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

There  appears  to  be  very  little  difference  between  the  Eureka  speci- 
mens and  those  described  by  Professor  Hall  from  the  Potsdam  sandstone 
of  Wisconsin.  Dr.  C.  A.  White  describes  similar  forms  from  Pioche,  Nevada, 
where  they  occur  in  strata  of  ("Primordial")  Cambrian  age. 

Formation  and  localities. — Cambrian.  Prospect  Mountain  Group,  in 
the  upper  beds  of  the  Secret  Canon  shale,  on  the  east  side  of  New  York 
and  Secret  Canons,  and  on  the  east  side  of  the  canon  at  the  eastern  side  of 
Euby  Hill.  Also  in  an  outcrop  of  limestone  on  the  west  side  of  the  foot- 
hills of  Combs'  Peak,  Antelope  Valley,  Eureka  District,  Nevada. 


PCECILOPODA. 
Genus  AGNOSTUS  Brongniart. 

Agnostus  Richmondensis,  n.  sp. 
Plate  is,  fig.  10. 

Cephalic  shield  moderately  convex,  length  and  breadth  equal,  sides 
scarcely  parallel,  rounding  in  front  into  the  broadly  rounded  anterior 
margin.  Glabella  three-fourths  the  length  and  a  little  more  than  one-third 
as  wide  at  the  base  as  the  width  of  the  shield,  it  is  elongate-conical  in  out- 
line, strongly  denned  by  the  dorsal  furrows,  and  with  the  anterior  third 
separated  by  a  distinct  transverse  furrow,  a  little  less  than  midway  between 
this  furrow  and  the  posterior  margin  a  short  furrow  penetrates  from  each 
side  towards  the  base  of  a  minute  tubercle  situated  on  the  median  line, 
two  oblique  furrows  cut  off  the  posterior  lateral  angles  as  two  small  rounded, 
triangular  node.s;  lateral  lobes  more  convex  than  the  glabella,  divided 
anteriorly  by  a  slight  median  furrow,  surrounded  by  a  narrow,  rim-like 
margin,  and  ornamented  by  slightly  irregular  depressed  lines  that  indent 
the  surface  from  the  margin  nearly  to  the  edge  of  the  strong  dorsal  furrows. 

Surface  smooth  under  an  ordinary  magnifying  power. 

Dimensions. — Length  and  breadth,  2.5mm;  depth  of  shield,  O.TS™11.  Tho- 
racic segments  and  caudal  shield  unknown. 


FOSSILS  OF  THE  CAMBRIAN. 

This  is  a  very  striking  and  pretty  species,  and  is  not  liable  to  be  mis- 
taken for  any  described  American  form,  and  it  appears  to  be  distinct  from 
any  European  species  known  to  me,  although  allied  in  a  slight  degree  to 
Agnostus  princeps  Salter. 

Formation  and  localities. — Cambrian.  Prospect  Mountain.'  limestone, 
upper  portion;  Ruby  Hill,  Richmond  mine,  700-foot  level;  and  east  slope 
of  the  northern  portion  of  Prospect  Mountain,  Eureka  District,  Nevada. 


Agnostus  seclusus,  n.  sp. 
Plate  be,  fig.  14. 

Cephalic  shield  strongly  convex,  a  little  longer  than  wide,  with  a  slight 
contraction  posteriorly  and  margined  by  a  narrow,  rim-like  border  that  has 
a  distinct  groove  between  it  and  the  lateral  lobes;  dorsal  furrows  well 
defined,  united  anteriorly,  but  not  dividing  the  lateral  lobes  in  front,  pos- 
teriorly each  turns  obliquely  outward,  a  short  distance  from  the  margin, 
cutting  off  the  inner  angle  of  the  lateral  lobes  Glabella  short  about  one- 
half  the  length  of  the  shield,  strongly  convex  and  squarely  truncated  in 
front;  at  about  the  anterior  third  a  broad,  short  furrow  penetrates  on  each 
side  a  short  distance,  and  posteriorly  a  rounded  node  is  separated  from 
each  lateral  angle  by  slight  furrows;  the  lateral  lobes  slope  rapidly  to  the 
marginal  groove  on  the  sides  and  more  gradually  to  the  front 

Surface  finely  granulose. 

Dimensions. — Length,  3mmj  breadth,  nearly  the  same ;  depth  of  shield, 
1.25mm. 

Thoracic  segments  and  caudal  shield  unknown. 

This  species  is  characterized  by  the  tumid,  short,  truncated  glabella 
and  broad  lateral  lobes. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group;  upper 
portion  Secret  Canon  shale,  on  the  east  side  of  Secret  Gallon,  Eureka  Dis- 
trict, Nevada. 


26  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Agnostus  bidens  Meek. 
Plate  ix,  figs.  13,  13  a. 

Agnostus  bi(]cns  Meek,  1873.     Sixth  Ann.  Rep.  IT.  S.  Geol.  Surv.  Territories  for  the 
year  1872,  p.  463. 

Cephalic  shield,  moderately  convex;  a  little  wider  than  long,  distinctly 
trilobed  and  bordered  by  a  rounded  margin,  with  a  rather  strongly  defined 
marginal  groove.  Glabella  convex,  narrow,  more  than  two-thirds  the 
length  of  the  shield,  converging  anteriorly  and  rounded  or  subangular  in 
front;  a  narrow,  transverse  furrow  enters  obliquely  from  each  side  poste- 
rior to  the  center  and  unites  just  in  advance  of  a  small  tubercle  on  the 
center  of  a  segment  defined  behind  by  a  transverse  furrow  that  bends  back- 
ward at  the  center;  between  the  latter  furrow  and  the  occipital  furrow,  a 
narrow  segment  widening  out  laterally,  is  distinctly  defined;  occipital  seg- 
ment very  narrow.  Dorsal  furrows  distinct,  united  in  front  of  the  glabella 
but  not  touching  the  frontal  border.  Lateral  lobes  strongly  convex  and 
sloping  rapidly  to  the  marginal  groove  from  the  somewhat  elevated  central 
portion;  frontal  lobe  about  half  as  wide  as  the  lateral  lobes  and  less 
convex. 

Thoracic  segments  unknown. 

The  caudal  shield  associated  with  the  above-described  head  has  all  of 
its  essential  elements,  and  there  is  little  doubt  but  that  it  belongs  to  the 
same  species.  It  is  provided  with  a  short  spine  or  process  on  each  posterior 
lateral  side  and  is  strongly  convex  and  trilobate;  the  axial  lobe  extends 
more  than  three-fourths  of  the  entire  length  and  has  an  elongate,  angular 
node  on  the  anterior  portion,  with  a  transverse  furrow  just  before  it  separat- 
ing a  narrow  anterior  portion,  and  in  some  examples  a  slight  transverse 
furrow  crosses  just  back  of  the  node;  this  is  obsolete  in  many  instances. 
The  dorsal  furrows  extend  backward  and  unite  posteriorly,  giving  the  axial 
lobe  a  conical  form;  lateral  lobes  strongly  convex  and  very  much  like 
those  of  the  associated  cephalic  shield.  Surface  of  both  shields  finely 
granulose  under  a  strong  magnifying  power. 


FOSSILS  OF  THE  CAMBRIAN. 


27 


Dimensions  of  cephalic  shield. — Length,  3.25mm;  width,  3.75mm;  caudal 
shield  as  4  is  to  5  in  length  and  breadth  respectively. 

A  comparison  of  specimens  made  after  the  manuscript  of  this  report 
was  written  shows  that  the  supposed  new  species  of  Agnostus  is  identical 
with  Mr.  Meek's  A.  Widens  from  the  Gallatin  River,  Montana,  also  that 
Ptycnoparia  Gallatinensis  occurs  in  association  with  it  in  Montana  and 
Nevada. 

Formation  and  localities. — Cambrian.  Prospect  Mountain  Group ; 
ranges  from  the  upper  portion  of  the  massive  Prospect  Mountain  lime- 
stone as  found  in  the  700-foot  level  of  the  Richmond  mine  at  Ruby  Hill 
and  on  the  east  slope  of  Prospect  Mountain,  to  the  summit  of  the  Ham- 
burg limestone,  near  the  Hamburg  mine,  and  into  the  base  of  the  Po- 
gonip  Group,  occurring  most  abundantly  in  the  upper  beds  of  the  Secret 
Canon  shale,  Eureka  District,  Nevada.  Also  in  the  Lower  Pogonip  Group 
on  Pogonip  Ridge,  White  Pine  District,  Nevada. 

Agnostus  commtmia  H.  &  W. 

Agnostus  communis  Hall  &  Whitfield,  1877.    Geol.  Expl.  Fortieth  Parallel,  vol.  iv, 
p.  228,  pi.  i,  figs.  28  and  29. 

This  species  has  a  vertical  range  similar  to  the  preceding,  and  occurs 
at  the  same  localities,  although  rarely  in  the  same  layer  of  rock.  The  orig- 
inal specimens  were  collected  by  the  geologists  of  the  Fortieth  Parallel 
Survey  from  the  White  Pine  Mining  District,  Nevada. 


Agnostus  Neon  H.  &  W. 

Agnostus  Neon  Hall  &  Whitfiekl,  1877.    Geol.  Expl.  Fortieth  Parallel,  vol.  iv,  p.  229, 
pi.  i,  figs.  26,  27. 

Associated  with  Agnostus  communis,  and.  having  essentially  the  same 
range  and  distribution  in  the  district,  the  original  types  coming  from  the 
Eureka  District,  Nevada,  by  the  same  survey. 


28  PALEONTOLOGY  OF  THE  EUKEKA  DISTKICT. 


Agnostus  prolongus  H.  &  W. 

Agnostus  prolongus  Hall  &  Wkitfield,  1877.     Geol.  Expl.  Fortieth  Parallel,  vol.  iv, 
p.  230,  pi.  i,  figs.  30,  31. 

This  form  was  originally  collected  in  the  Eureka  District,  but  it  is 
rare,  having  been  found  only  in  the  Hamburg  belt  of  limestone  northeast 
of  Adams  Hill,  and  on  the  west  side  of  Sierra  Canon,  Eureka  District,  Ne- 
vada. 


Genus  OLENELLUS  Hall. 

Olenellus  Iddingsi,  n.  sp. 
Plate  ix,  fig.  12. 

General  outline  of  the  head  roughly  subtriangular,  with  the  length 
one-half  the  breadth  of  the  posterior  border;  strongly  convex;  the  rather 
narrow,  rounded  rim  bordering  the  anterior  margin  suddenly  becomes 
thickened  and  rounded  opposite  the  eyes  and  is  extended  back  in  the  short, 
strong,  slightly  curved  genal  spines,  the  narrow  posterior  marginal  border 
uniting  with  it  at  the  genal  angles.  Glabella  elongate,  narrow,  divided  by 
four  transverse  furrows  into  five  lobes;  the  anterior  is  round,  tumid,  and  ex- 
panded laterally,  while  the  four  posterior  are  narrow,  transverse,  of  equal 
size,  and  with  their  sides  parallel;  occipital  ring  and  furrow  not  recog- 
nized; eyes  lunate,  situated  opposite  the  central  lobes  of  the  glabella. 
Facial  suture  in  front  of  the  eye  unknown;  back  of  the  eye  it  extends 
obliquely  outward  and  backward,  cutting  the  posterior  margin  about  two- 
thirds  the  distance  from  the  glabella  to  the  postero-lateral  spine. 

Thorax  and  pygidium  unknown. 

The  specific  name  is  given  in  honor  of  Mr.  J.  P.  Iddings,  the  discov- 
erer of  the  type  specimen. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  in  an 
arenaceous  shale  above  the  quartzite  capping  Prospect  Peak,  Eureka  Dis- 
trict, Nevada. 


FOSSILS  OF  THE  CAMBRIAN.  29 

Olenellus  Gilbert!  Meek. 
Plate  ix,  fig.  10,  16 a;  pi.  xxi,  fig.  13. 

Olenellus  Gilberti  Meek,  1874.     (Manuscript.) 

Olenellus  Gilberti  White,  1874.     Geog.  and  Geol.  Expl.  and  Surv.  West  lOOtb  Merid.; 

Preliin.  Rep.  Invert.  Foss.,  7. 
Olenus  (Olenellus)  Gilberti  Meek,  1875.    Geog.  and  Geol.  Surv.  West  100th  Merid.,  vol. 

iii,  Geology,  p.  182. 
Olenellus  Gilberti  White,  1875.    Geog.  and  Geol.  Expl.  and  Surv.  West  100th  Merid., 

vol.  iv,  pt.  i,  p.  44,  pi.  ii,  figs.  3  a,  e. 

Head  semioval  in  outline,  moderately  convex,  margined  all  around  by 
a  narrow  wire-like  rim,  which  is  produced  at  the  genal  angles  into  slender 
spines  Glabella  elongate,  narrowing  slightly  towards  the  front;  general 
surface  moderately  convex  anteriorly,  becoming  less  so  back  of  the  frontal 
lobe;  the  glabellar  furrows  penetrate  obliquely  backward  nearly  to  the 
median  line,  with  the  exception  of  the  second  anterior  pair,  which  are 
shown  by  elongate  depressions  on  the  line  of  division  of  the  second  and 
third  anterior  lobes,  the  two  lobes  uniting  laterally  so  that  the  furrows  do 
not  extend  to  the  dorsal  furrows;  the  frontal  glabellar  lobe  is  convex,  oval 
in  outline,  with  a  tendency  in  some  examples  to  become  angular  in  front; 
the  two  posterior  lobes  are  subequal  in  size;  the  occipital  ring  and  furrow 
well  denned;  eyes  elongate,  narrow,  arching  outward  from  the  point  where 
the  anterior  glabellar  furrow  meets  the  dorsal  furrow,  and  backward 
to  the  posterior  glabellar  furrow;  dorsal  furrows  shallow;  the  fixed  and 
free  cheeks  united  form  a  broad  slope  from  the  eye  to  the  lateral  margins 
and  anteriorly  merge  into  the  long  frontal  limb.  The  facial  sutures  cannot 
be  traced  in  any  of  the  specimens.  Thorax  and  pygidium  unknown. 

The  above  description  is  drawn  from  specimens  obtained  in  the  Eureka 
District.  The  differences  between  them  and  the  type  specimens  are  almost 
entirely  in  the  frontal  limb,  the  former  having  a  much  broader  space  between 
the  front  of  the  glabella  and  marginal  rim.  In  some  examples  from  the 
typical  locality  of  the  species  at  Pioche,  Nevada,  the  frontal  limb  is  much 
broader  than  in  those  illustrated  in  Dr.  White's  report,  the  Eureka  form 
appearing  to  be  specifically  identical  with  them. 

Formation  and  loctdity. — Cambrian.  Prospect  Mountain  Group,  in  an 
arenaceous  shale  above  the  quartzite  capping  Prospect  Peak,  Eureka  Dis- 
trict, Nevada. 


30  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Olenellus  Howelli  Meek. 
Plate  ix,  figs.  15,  15  a,  b,  and  pi.  xxi,  figs.  1, 9. 

Olenellus  Howelli  Meek,  1874.     (Manuscript.) 

Olenellus  Howelli  White.  1874.    Geog.  and  Geol.  Expl.  and  Surv.  West  100th  Merid. ; 

Prelim.  Rep.  Invert.  Foss.,  p.  8. 
Olenus  (Olenelluts)  Howelli  Meek,  1875.    Geog.  and  Geol.  Surv.  West  100th  Merid.,  vol. 

iii,  Geology,  p.  183. 
Olenellus  Howelli  White,  1875.     Geog.  and  Geol.  Expl.  and  Surv.  West  100th  Merid., 

vol.  iv,  pt.  1,  p.  47,  pi.  ii,  figs.  4  a,  b. 

The  general  outline  of  the  head  of  the  adult  is  semi-elliptical  or  semi- 
circular and  more  or  less  strongly  convex.  The  margin  is  bordered  by  a 
narrow,  rounded  rim  which  becomes  thickened  near  the  genal  angles  and 
continues  posteriorly  as  rather  short,  sharp  spines.  The  glabella  is  elon- 
gate and  more  or  less  expanded  in  front  and  behind,  contracting  a  little 
midway ;  four  pairs  of  glabellar  furrows  penetrate  from  each  side ;  they  are 
somewhat  strongly  impressed  on  each  lateral  third  of  the  width  of  the  gla- 
bella, becoming  more  shallow  as  they  pass  into  the  more  shallow  furrow  that 
unites  them  across  the  center;  in  younger  specimens  this  furrow  is  undis- 
tinguishable  from  the  lateral  furrows  and  they  all  unite  as  one  distinct  fur- 
row crossing  the  glabella  from  side  to  side,  and  even  in  the  adults  this  fea- 
ture is  strongly  marked  in  some  individuals;  the  anterior  lobe  of  the  gla- 
bella is  more  or  less  tumid,  subhemispherical  or  a  little  transverse  and  wider 
than  the  greatest  width  of  the  glabella  immediately  behind  it;  the  next  pos- 
terior lobe  is  rather  narrow  and  transverse,  differing  from  the  two  next  pos- 
terior lobes,  which  arer  wider  and  curved  a  little  forward  at  the  ends,  by  the 
direction  of  the  furrows ;  the  posterior  lobe  corresponding  to  the  occipital 
ring  or  segment  is  broad  and  essentially  of  the  same  character  as  that  pre- 
ceding it;  the  furrow  separating  them  is  very  shallow  at  the  center  and  in- 
clined obliquely  backward  at  the  sides;  a  small  node  occurs  on  one  example 
at  the  center  of  the  occipital  ring. 

Eyes  elongate,  narrow,  and  arching  from  opposite  the  anterior  glabellar 
lobe  to  opposite  the  occipital  furrow.  The  dorsal  furrows  are  narrow,  dis- 
tinctly but  not  deeply  impressed.  Fixed  cheeks  a  little  expanded  anteriorly 
and  scarcely  more  than  a  line  between  the  elongate  palpebral  lobes  and  the 
dorsal  furrows,  while  posteriorly  they  merge  into  the  small  triangular  late- 
ral limbs;  frontal  limb  obsolete.  Free  cheeks  large,  roughly  subtriangular 


FOSSILS  OF  THE  CAMBRIAN. 


31 


in  outline,  their  posterior  margin  marked  by  a  more  or  less  prominent  curve 
or  angle  between  the  genal  angle  and  the  inner  end  of  the  margin. 

The  facial  suture  cuts  the  anterior  margin  some  distance  outside  the 
line  of  the  outer  margin  of  the  glabella  and  passes  obliquely  inward  to  the 
anterior  angle  of  the  eyelobe;  curving  around  the  outer  margin  of  this,  it 
passes  obliquely  outward  to  the  posterior  margin,  cutting  it  about  midway 
between  the  glabellar  lobe  and  the  outer  margin  of  the  genal  angle. 

The  surface  of  the  glabella  is  beautifully  ornamented  with  transverse, 
fine,  irregularly-waving,  subimbricating  lines  that  give  the  appearance  of 
imbricating  lamellae  resting  one  under  the  other  from  before  backward;  this 
feature  is  only  seen  on  the  most  perfectly  preserved  specimens;  the  surface 
of  the  cheeks  is  slightly  granulose  under  a  strong  magnifying  glass.  The 
test  itself  is  very  thin  and  fragile  and  is  usually  broken  away. 

Thorax  and  pygidium  unknown.  Portions  of  the  plenral  lobe  of  sev- 
eral thoracic  segments  were  found  in  association  with  the  heads  of  this  and 
the  preceding  species  that  show  that  the  pletiron  is  prolonged  in  all  of  them, 
in  one  more  than  the  others,  and  that  the  portions  of  the  segments  preserved 
are  typical  in  their  character  of  the  genus;  the  pleural  groove  is  strong  and 
broad,  continuing  well  out  towards  the  extremity  beyond  the  geniculation. 

The  description  of  the  cephalic  shield  is  that  of  what  is  considered  as 
the  normal,  adult  type  of  the  head,  and  omits  altogether  the  phases  of  this 
remarkable  species  that  are  shown  in  its  various  stages  of  growth  and  devel- 
opment. A  note  and  several  figures  in  illustration  are  appended  that  were 
prepared  after  the  first  study  of  the  collections. 

The  above  description  was  written  in  1880  under  the  impression  that 
the  species  was  nndescribed.  On  obtaining  a  large  number  of  specimens 
in  1882,  it  was  found  that  the  species  could  be  connected  with  Olemllus 
Howellij  a  species  founded  by  Mr.  Meek  on  a  single  large  head  from  the 
Cambrian  at  Pioche,  Nevada.  On  a  direct  comparison  with  the  type  the 
larger  specimens  are  seen  to  be  essentially  the  same  if  we  allow  for  the 
compression  of  the  Eureka  specimens  in  the  sandy  shale. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group  in  an 
arenaceous  shale  above  the  quartzite  capping  the  summit  of  Prospect  Peak, 
Eureka  District,  Nevada. 


32  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

OBSERVATIONS  ON  OLENELLUS  HOWELLI. 

Plate  xxi,  figs.  1-17. 

The  study  of  the  material  in  the  collection  illustrating  this  species  hav- 
ing developed  some  interesting  facts,  they  are  here  discussed  under  two 
heads:  First,  the  character  of  the  species  during  the  later  stages  of  its 
development  as  far  as  known;  second,  the  relation  of  the  species  to  other 
species  of  the  same  genus,  and  to  certain  species  of  the  genus  Paradoxides. 

I.  A  seiies  of  specimens  illustrating  the  principal  embryonic  and  abnor- 
mal features  of  .development  are  figured  on  plate  xxi,  figs.  1-9,  the  details 
of  which,  and  also  the  figures  up  to  fig.  18,  are  given  in  the  explanation 
accompanying  the  plate. 

Contour  of  the  head. — The  smallest  specimen  of  the  head  observed,  rig. 
1,  is  2.5mm  in  length,  and  resembles  in  its  outline  the  larger  head,  fig.  3, 
which  has  a  length  of  7.5mm,  as  is  seen  more  clearly  by  comparing  the  latter 
with  the  enlarged  figure  of  fig.  1,  on  plate  ix,  fig.  156.  Between  figs.  1  and 
3,  in  size,  is  the  form  represented  by  fig.  2,  which  is  transversely  quadri- 
lateral in  outline,  with  the  genal  angles  and  spines  carried  forward  to  form 
antero-lateral  angles  on  a  line  with  the  frontal  margin  of  the  head  and  the 
geniculation  of  the  posterior  margin,  which  is  so  strongly  marked  in  fig  1, 
is  still  further  increased  to  form  an  angle  of  nearly  90°,  which,  from  its 
position,  might  be  incorrectly  viewed  as  the  true  genal  angle  if  the  anterior 
spines  were  broken  away  or  obscured  and  the  course  of  development  of  the 
species  unknown.  In  fig.  4  the  genal  spines  are  still  more  anterior  than  in 
the  smaller  forms  (figs.  1  and  3),  presenting  a  transition  stage,  not  consider- 
ing the  size  of  the  head,  but  the  general  form,  between  figs.  1  and  2  or  2 
and  3,  the  angles  of  the  posterior  margin  x  x,  are  also  more  obtuse  and  the 
frontal  margin  broadly  rounded.  Through  the  forms  represented  by  figs. 
3  to  5  the  modification  of  these  features  is  very  uniform  to  the  normal  adult 
type  of  the  contour  of  the  head,  as  shown  by  fig.  6.  In  figs.  7  and  8,  how- 
ever, which  are  considerably  larger  specimens,  the  angularity  of  the  pos- 
terior margin  is  a  prominent  feature,  the  genal  angles  being  advanced  as  in 
the  forms  before  fig.  6.  In  fig.  9  the  outline  is  still  further  diversified  by 
having  the  angularity  of  the  posterior  margin  and  the  position  of  the  genal 


FOSSILS  OF  THE  OAMBEIAN. 


33 


spine  on  one  side  differing  from  that  on  the  other.  Fig.  6  is  considered  as 
nearly  typical  of  the  adult  outline  of  the  head  as  the  largest  specimen 
found,  and  a  number  of  medium  size  have  the  same  form.  The  genicula- 
tion  of  the  posterior  margin  is  an  embryonic  character  that  is  singularly 
persistent  in  many  examples  of  otherwise  adult  character.  In  figs.  12,  13, 
and  14  the  adult  form  of  the  head  of  three  other  species  of  the  genus  is 
shown. 

Glabella. — There  is  not  as  decided  a  change  proportionally  between  the 
glabella  of  the  smallest  individual  and  that  of  the  normal  adult  as  there  is 
in  the  outer  contour  of  the  head;  still  it  is  to  be  observed,  that  the  dorsal 
furrows  are  not  continuous  but  interrupted  by  the  ocular  ridges  that  cross 
them  and  unite  with  the  frontal  lobe  of  the  glabella  (figs.  2,  4,  and  6),  a  feat- 
ure unknown  in  the  adult,  that  in  the  younger  individuals  the  glabellar 
furrows  extend  entirely  across  the  glabella,  while  in  the  older  ones  they  are 
more  or  less  interrupted  or  united  only  by  very  shallow  transverse  furrows 
at  the  center. 

Eyes. — The  usual  form  of  the  eye  of  the  adult  in  this  genus  is  shown 
in  figs.  7,  8,  9,  12,  and  14,  where  it  is  narrow,  broadly  arching  outward,  and 
with  a  more  or  less  narrow  palpebral  lobe  close  to  the  glabella.  In  tracing 
the  development  of  the  eye  of  Olenellus  Howelli,  it  is  found,  in  the  earliest 
stage  with  which  we  are  acquainted,  to  be  situated  distant  from  the  glabella 
toward  the  center  of  the  cheek  and  united  to  the  anterior  lobe  of  the  gla- 
bella by  a  strong  ocular  ridge  that  crosses  and  interrupts  the  continuity  of 
the  dorsal  furrow  (see  fig.  2  and  enlargement  of  fig.  1  on  plate  ix,  fig. 
15&).  There  is  considerable  variation  in  the  relative  position  of  the  eye 
and  the  length  and  strength  of  the  ocular  ridge  in  different  examples  of 
the  head.  In  fig.  2  the  ocular  ridge  of  the  left  side  is  elevated,  and  with 
the  high  margin  of  the  eyelobe  partially  incloses  the  depressed  area  within, 
while  on  the  right  side  of  the  same  individual  both  the  ridge  and  eye  are 
less  elevated,  and  the  ocular  ridge  being  shorter  the  eye  is  brought  in 
nearer  to  the  glabella.  In  fig.  4  the  ocular  ridge  is  narrower  at  the  point 
of  union  with  the  glabella  and  attached  farther  back  near  the  posterior 
margin  of  the  frontal  lobe.  Frequently  the  longitudinal  axis  of  the  eye  is 
slightly  oblique  from  its  anterior  end  backward  and  outward.  With  the 
3  o  D  w 


34  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

increase  in  size,  these  features  usually  disappear,  although  in  fig.  6  there 
is  an  exception,  as  they  are  retained  in  a  modified  degree  after  other  accom- 
panying embryonic  features  of  the  head  have  disappeared.  Between  the 
eye  and  glabella,  when  the  former  is  situated  well  out  on  the  cheek,  a  small 
round  or  oval  boss  occurs,  as  shown  in  figs.  2,  3,  4,  and  6. 

Facial  suture. — The  course  of  the  facial  suture  in  front  of  the  adult 
head  is  shown  by  the  free  cheek,  fig.  1 7  (s).  Of  its  variation  from  this  course 
during  the  development  of  the  individual  nothing  is  known  from  actual 
observation,  but  from  the  fact  that  the  relative  position  of  the  eye  changes,  it 
is  probable  almost  to  a  certainty,  that  its  direction  is  somewhat  varied,  and 
we  know  that  such  is  the  case  in  its  direction  back  of  the  eye  when  the 
latter  is  situated  out  on  the  cheek  or  near  the  glabella.  Back  of  the  eye, 
in  all  the  instances  in  which  it  has  been  observed,  its  direction  is  slightly 
outward,  with  a  sigmoidal  curvature  to  the  angle  of  the  posterior  margin, 
or,  in  its  absence,  at  the  broad  curve  denoting  the  position  of  the  angle 
about  midway  between  the  dorsal  furrow  and  the  genal  angle,  figs.  3,  4,  5, 
and  6.  In  the  large  adult  specimens  its  course  was  probably  as  indicated 
by  the  traced  line  in  fig.  9,  where  it  is  much  the  same  as  in  the  genus  Ogygia 
or  Dicellocephalus,  and  even  more  so  in  the  cheek,  fig.  17,  if  it  cut  the  poste- 
rior margin  at  the  angle  #,  as  it  does  in  all  known  cases  in  the  smaller  speci- 
mens, figs.  3,  4,  5,  and 6.  Comparing  this  with  the  direction  of  the  stages  of 
growth  shown  in  figs.  3  and  4,  where  another  generic  group  is  suggested  by 
its  Paradoxides-like  course,  the  contrast  is  very  striking. 

In  the  adult  specimens  of  Olenellus  Gilberti  and  0.  Vermontana  the 
course  of  the  facial  suture  is  almost  directly  backward  from  the  eye  to  the 
margin,  corresponding  nearly  to  the  line  o  o,  of  fig.  17,  and  terminating  far 
within  the  angle  x.  That  the  course  of  the  suture  was  the  same  in  the 
larger  heads  of  0.  Howelli  is  not  probable,  as  the  head,  fig.  6,  shows  it  ter- 
minating at  the  place  of  the  angle  x,  But  the  fact  that  in  the  closely  allied 
species  0.  Gilberti  the  termination  is  between  the  angle  and  the  dorsal  suture 
would  lead  to  looking  for  it  there  in  0.  Howelli;  that  its  course,  if  not  con- 
stant in  the  large  adults,  is  as  in  fig.  6,  only  adds  another  anomalous  feature 
to  this  strange  species. 

Mode  of  development. — The  normal  development  of  a  trilobite  from  the 


FOSSILS  OF  THE  CAMBItfAK 

earliest  embryonic  condition  with  which  we  are  acquainted  to  the  adult 
form  is  marked  by  the  disappearance  of  the  embryonic  characters  one  by 
one  as  the  individual  increases  in  size  and  assumes  more  and  more  the  feat- 
ures of  the  fully  developed  animal,  all  of  which  usually  takes  place,  except 
in  size  and  surface  ornamentations,  when  it  is  quite  small.  The  retaining 
of  an  embryonic  feature  after  the  individual  has  passed  in  size,  or  any  other 
character,  the  stage  at  which  it  usually  disappears  in  the  regular  course  of 
the  development  of  the  species,  is  an  exceedingly  rare  occurrence,  and  is 
unknown,  to  our  own  knowledge,  except  in  the  increase  in  size  of  the  body 
in  certain  species,  so  that  in  their  course  of  development  certain  individuals 
are  in  fact  larger  than  those  of  the  same  species  having  a  greater  number  of 
segments  in  the  thorax  and  consequently  more  advanced  in  development. 
M.  Barrande  has  shown  this  to  be  the  case  in  the  development  of  Arethusina 
Konincki,  Proetus  decorm,  and  P.  venustus*  and  we  have  observed  it  in 
Triarthrus  Beckij  where  the  relative  size,  proportional  to  the  development, 
is  very  marked,  e.  g.,  an  individual  with  13  segments  in  the  thorax  is  24mm 
in  length,  and  one  with  16  segments  but  16.5mm  long,  while  the  fully-grown 
example  of  16  segments  reaches  a  length  of  53mm,  and  some  with  13  seg- 
ments are  but  7mm  in  length.2 

This  peculiarity  of  growth  is  shown  in  the  species  mentioned  only  by 
the  thorax,  for  if  we  take  the  head  apart  from  it  there  is  little  or  nothing  to 
prove  that  its  size  is  not  proportional  to  the  stage  of  development;  but  in 
Olenellus  Howelli  the  head  proves  this  to  be  otherwise,  and  there  may  be  added 
to  the  statement,  that  in  certain  species  the  size  is  not  proportional  to  the  num- 
ber of  liberated  segments  in  the  thorax,  that  in  other  species  the  size  of  the 
head  is  not  always  proportional  to  its  stage  of  development.  It  is  greatly 
to  be  regretted  that  the  thorax  and  pygidium  are  not  preserved,  so  that  a 
direct  comparison  of  those  parts  could  be  made  with  abnormal  conditions 
of  development  in  other  genera  and  species. 

Having  shown  that  the  peculiar  development  of  this  species,  exhibited 
in  the  acceleration  and  retardation  of  growth  in  individuals  as  compared 
with  each  other,  is  in  a  measure  comparable  with  the  peculiarities  of  growth 

'Systeme  Silurien  de  la  Bohfime,  vol.  i,  p.  268,  1852. 

"Trans.  Albany  Inst.,  vol.  x.    Fossils  of  the  Utica  Slate,  p.  29,  1879. 


36  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

in  some  other  species,  a  few  of  the  questions  arising  from  the  study  of  the 
stages  of  growth  observed  will  be  spoken  of  as  they  are  shown  in  the  first 
nine  figures  on  plate  xxi. 

It  is  impossible  to  imagine  that  the  course  of  development  was  by  size 
through  figs.  1,  2,  3,  4,  and  5;  but  if  we  take  out  the  two  forms  figs.  2  and 
4,  those  remaining,  figs.  1,  3,  5,  and  6,  constitute  a  very  good  advancing 
series  and  the  larger  specimens,  figs.  7,  8,  9,  might  be  considered  as  illus- 
trating the  principle  that  the  size  is  not  proportional  to  the  stage  of  develop- 
ment. The  two  forms  taken  out,  figs.  2  and  4,  however,  prevent  the  first,  if 
we  consider  them  as  belonging  to  the  same  species,  as  appears  to  be  the 
case.  They  are  associated  with  such  forms  as  3,  5,  &c.,  and  the  two  species 
Olenellus  Gilbert^  plate  ix,  fig  16,  plate  xxi,  fig.  13,  and  O.Iddingsi,  plate  ix, 
fig.  12,  in  the  same  hard  specimens  of  arenaceous  shale,  and,  although  fig. 
2  is  an  extreme  form,  fig.  4  is  a  gradation  in  form  to  such  forms  as  figs.  1 
and  3.  It  is  observed  that  figs.  7,  8,  and  9  precede  6  in  the  stage  of  devel- 
opment of  the  contour  of  the  head,  at  the  same  time  showing  a  more  accel- 
erated development  in  the  form  of  the  eye.  The  eye  of  fig.  5  is  more  ad- 
vanced than  that  of  fig.  6,  while  the  posterior  outline  of  the  head  is  more 
embryonic  in  its  character.  With  these  examples  it  is  readily  conceived 
that  figs.  2  and  4  are  enlarged  examples  of  the  forms  that  preceded  fig.  1  in 
development,  and  the  eye  of  fig.  2  supports  this  view,  as  it  is,  in  its  strongly 
developed  ocular  ridge,  which  is  more  marked  than  in  fig.  1,  and  more  an- 
terior in  relation  to  the  frontal  lobe  of  theglabella,  essentially  more  embryonic; 
and  the  position  of  the  genal  angles  and  spines  is  either  a-  decided  embryonic 
feature,  or  a  sport  that,  with  fig.  4,  to  connect  it  with  figs.  1  or  3,  would  not 
be  considered  as  probable. 

Was,  then,  the  probable  course  of  development  of  this  species,  before 
it  reached  the  character  of  fig.  1,  through  earlier  stages  to  a  form  like  fig.  2, 
thence  to  figs.  4,  1,  2,  5,  and  so  on  to  the  adult? 

In  the  development  of  Olenellus  asaphoides,  as  given  by  Mr.  Ford,3  the 
youngest  stage  is  about  2mm  in  diameter  and  nearly  circular  in  outline,  the 
genal  angles  and  spines  are  situated  close  in  by  the  side  of  the  facial  suture, 
as  it  is  subsequently  developed,  and  there  appears  to  be  no  doubt  but  that 

8Amer.  Journ.  Sci.,  3rd  ser.,  vol.  xiii,  p.  265,  figs.  1-4,  1877.     Ibid.,  vol.  xxii,  p.  250,  1881. 


FOSSILS  OF  THE  CAMBRIAN. 


37 


it  is  embryonic  and  representative  of  one  of  the  earlier  stages  of  growth 
of  the  species.  The  second  stage,  of  which  an  outline  figure  is  given 
on  plate  xxi,  fig.  10,  has  changed  somewhat,  but  the  essential  elements  re- 
main, and  in  fig.  1 1  there  is  a  still  greater  expansion  of  the  posterior  margin 
of  the  head  and  the  genal  angles  are  carried  slightly  forward.  There  are 
probably  several  intermediate  forms  between  figs  10  and  11  that  have  not 
as  yet  been  discovered,  but  for  the  present  comparison  they  may  be  dis- 
pensed with,  as  in  fig,  1  i  we  have  a  form  that  may  be  compared  in  the 
contour  of  the  head  with  our  figs.  1  and  3 ;  the  genal  angles  are  forward  of 
the  line  of  the  posterior  margin,  and  strong  obtuse  angles  occur  where  the 
facial  sutures  cut  the  latter  at  x  x.  In  fig.  1 2  the  normal  adult  form  of  the 
head  of  this  species  is  outlined.  Reviewing  the  development  thus  hastily 
sketched,  it  is  seen  that  the  form  fig.  11  is  intermediate  between  figs.  10 
and  12,  and  representative  of  the  group  of  forms  found  in  O.  Rowelli,  be- 
tween fig.  6  and  the  earlier  forms  preceding  fig.  1  in  size,  fig.  6  being 
considered  as  nearest  the  adult  type  in  the  contour  of  the  head.  Without 
more  data,  it  is,  perhaps,  conjectural  to  consider  that  the  forms  preceding 
fig.  1  were  like  figs.  2  and  4,  and  that  preceding  these  the  earlier  stages  of 
0.  asaphoides  were  represented,  the  forms  figs.  2,  4,  1,3,5  occupying  the 
position  in  development  taken  by  1 1  in  the  latter  species.  At  present  no 
other  view  seems  as  reasonable,  unless  it  is  thought  that  fig.  2  represents 
the  extreme  embryonic  tendency  of  the  species,  a  course  of  development 
the  reverse  of  that  of  Olenellus  asapJioides,  or  any  known  species  of  the  tri- 
lobita,  and  one  not  at  all  probable  in  this  instance. 

II.  Eelations  to  other  species  and  genera. — The  difficulty  met  with  in 
comparing  the  abnormal  development  of  this  species  with  that  of  other 
species  in  which  the  thorax  and  pygidium  are  known  is  also  felt  in  study- 
ing its  relations  to  various  species  and  genera  in  which  the  structure  of  the 
entire  body  is  known,  restricting  as  it  does  all  comparisons  to  the  head. 

The  species  associated  with  Olenellus  Howelli  are  0.  Gilbert!,  plate  ix, 
fig.  16,  plate  xxi,  fig.  13,  and  0.  Iddingsi,  plate  ix,  fig.  12.  The  smallest 
head  of  the  former,  fig.  13,  is  about  the  size  of  fig.  2  of  the  same  plate,  but 
does  not  present  the  strong  embryonic  features  of  the  latter.  In  compari- 
son with  the  adult  head  of  the  same  species,  plate  ix,  fig.  16,  it  is  observed 


38  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

that  the  eyes  in  the  smaller  individual  are  a  little  distant  from  the  glabella  and 
united  to  it  by  a  very  short  ocular  ridge ;  otherwise  no  embryonic  features 
are  indicated.  The  example  of  the  head  of  0.  Iddingsi  is  still  smaller,  but 
it  does  not  present  any  recognized  embryonic  features. 

Olenellus  Gilberti  and  0.  Howelli  also  occur  at  the  same  relative  geologic 
horizon,  at  Pioche,  Nevada,  130  miles  (209.2  kilometers)  distant.  The  for- 
mer species  in  that  locality  is  noticeable  in  having,  in  the  smaller  specimens 
observed,  an  obtuse  angle  in  the  posterior  margin  of  the  head  midway 
between  the  genal  angle  and  the  glabella  (see  outline,  fig.  14,  plate  xxi).  In 
the  larger  specimens  the  angle  is  near  the  outer  portion  of  the  margin  or  a 
little  within  the  postero-lateral  angle.  The  facial  suture  back  of  the  eye 
is  quite  unlike  that  of  0.  Howelli,  as  shown  for  the  latter  in  figs.  5  and  6, 
and  cuts  the  posterior  margin  between  the  angle,  x  x,  of  the  margin  and 
the  glabella,  as  seen  in  figs.  14  and  17.  In  comparing  with  0.  Thompsoni  and 
0.  Vermontana  Hall,  from  the  Georgia  slates  of  Vermont,  it  is  only  to  be 
observed  that  in  the  former  species  the  general  features  of  the  adult,  as  far 
as  known,  appear  to  be  the  same,  and  that  in  the  latter  the  facial  suture  has 
the  same  course  back  of  the  eye  as  in  0.  Gilberti,  and  Prof.  R.  P.  Whitfield 
has  shown  me  a  specimen  in  the  collection  of  the  American  Museum  of 
Natural  History  that  is  marked  by  a  very  short  spine  on  the  obtuse,  rounded 
angle  of  the  posterior  margin,  a  short  distance  within  the  postero-lateral 
angle,  a  character  not  observed  in  any  other  species  of  the  genus. 

Mention  has  been  made  of  Olenellus  asaphoides  and  certain  resemblances 
in  the  contour  of  its  head  at  the  stage  of  development  represented  by  fig.  11, 
and  that  of  the  head  of  0.  Howelli  as  seen  in  figs.  1,  3,  5,  etc.  The  curious 
interocular  spines  of  the  former  have  not  been  seen  in  0.  Howelli.  Mr.  Ford 
has  called  attention  to  the  Paradoxides-like  run  of  the  posterior  margin  of 
the  head,  g  x,  xg,  fig.  11,  and  states  that  it  disappears  altogether  during  the 
embryonic  life  of  that  species.  We  have  shown  that  it  is  extravagantly 
developed  in  0.  Howelli,  even  to  the  extent  of  changing  the  entire  contour 
of  the  head,  fig.  2,  and  that  it  persists  in  the  adult  stage  of  many  individuals 
of  this  species,  and  is  also  present  in  0.  Gilberti  and  0.  Vermontana. 

In  all  the  observed  specimens  of  0.  Howelli  showing  the  facial  suture 
back  of  the  eye  the  posterior  margin  is  cut  by  it  at  the  angle  within  the 


FOSSILS  OF  THE  CAMBRIAN. 

postero-lateral  angle,  as  Mr.  Ford  has  pointed  out  for  the  form,  fig.  1 1 ,  of  O. 
asaphoides,  and  also  in  the  genus  Paradoxides. 

Attention  is  again  called  to  the  direction  of  the  facial  suture  back  of 
the  eyes,  in  figs.  3  and  4,  and  the  position  and  obliquity  of  the1  eyes  in  re- 
lation to  the  median  line  of  the  glabella,  characters  of  Paradoxides,  as  seen 
in  P.  spinosus.  Of  all  the  species  of  the  latter  genus,  P.  Kjerulfi*  alone 
shows  the  presence  of  an  ocular  ridge  uniting  the  eye  and  the  frontal  lobe 
of  the  glabella,  fig.  15  (a),  a  feature  so  prominent  in  the  young  of  0.  Howelli, 
as  well  as  the  small,  rounded  protuberance  between  the  eye  and  the  glabella, 
shown  in  Linnarsson's  fig.  2,  of  P.  Kjerulfi.  The  latter  character  Mr.  Ford 
discovered  in  the  young  of  0.  asaphoides,  and  noted  its  resemblance  to  the 
same  in  P.  Kjerulfi.  The  ocular  ridge,  a  feature  in  the  latter  that  is  per- 
manent, is  also  present  in  the  young  of  0.  Howelli,  but  disappears  in  the 
adult,  adding  in  this  another  link  to  the  argument  so  admirably  brought 
forward  by  Mr.  Ford  to  show  the  genetic  relation  of  the  two  genera. 

Resume. — The  study  of  the  head  of  Olenellus  Howelli  proves: 

First.  That  in  certain  individuals  of  this  species  the  existence  of  em- 
bryonic features  continues  long  after  the  individual  has  reached  the  size  at 
which  such  features  are  usually  lost  in  the  process  of  development  of  other 
species  of  the  genus. 

Second.  That  in  individuals  otherwise  developed  equally  in  all  respects 
some  one  of  them  may  have  a  characteristic  feature,  such  as  the  eye  or  the 
genal  angle,  developed  to  a  greater  or  less  degree  than  in  the  others,  and 
that  this  feature  may  persist  even  after  the  individual  having  it  has  passed 
in  size  or  other  characters  the  stage  at  which  it  is  usually  lost 

Third.  That  the  development  of  certain  characters  went  on  in  an  unequal 
degree  in  the  corresponding  parts  of  the  same  individual,  and,  finally,  that 
certain  features  present  in  the  younger  individuals  and  disappearing  during 
the  subsequent  growth  are  permanent  features  in  some  species  of  the  genus 
Paradoxides. 

*  0 fversigt  af  Kongl.  Vetenskaps-Akademiens  Forhandlingar,  N:o.  6,  Stockholm,  p.  790,  Tafl. 
xvi,  figs.  1,  2.  1871. 


40  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  DICELLOCEPHALUS  Owen. 
Dicellocephalus  bilobatus  H.  &  W. 

Dicellocephalus  bilobatus  Hall  &  Whitfleld,  1877.    Geol.  Expl.  Fortieth  Parallel,  vol.  iv, 
p.  226,  pi.  2,  fig.  36. 

This  species  was  founded  on  a  pygidium  having  a  bilobed  posterior 
border,  collected  in  the  Eureka  District  by  the  geologists  of  the  Fortieth 
Parallel  Geological  Survey.  The  same  character  of  pygidium  was  obtained 
by  the  present  survey  in  the  upper  beds  of  the  Cambrian,  on  the  east  side 
of  the  Sierra  Valley,  east  of  Pinnacle  Peak,  Eureka  District,  Nevada. 

Dicellocephalus  Osceola  Hall. 
Plate  ix,  fig.  25. 

DikelocepJialus  osceola  Hall,  1863.    Sixteenth  Ann.  Kep.  N.  Y.  State  Cab.  Nat.  Hist., 
p.  146,  pi.  x,  fig.  1«;  pi.  vii,  fig.  49? 

Original  type  from  the  Potsdam  sandstones  at  Osceola  Mills,  State  of 
Wisconsin. 

A  comparison  of  the  Nevada  specimens,  consisting  of  the  glabella  and 
fixed  cheeks,  with  the  type  example  of  the  species  in  the  American  Museum 
collection,  shows  such  a  strong  specific  identity  of  the  parts  preserved  that 
there  is  little  doubt,  with  our  present  information,  but  that  they  belong  to 
one  and  the  same  species. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  upper 
portion,  on  ridge  north  of  the  Dunderberg  mine,  Eureka  District,  Nevada. 

Dicellocephalus  nasutus,  n.  sp. 
Plate  x,  fig.  15. 

Glabella  and  fixed  cheeks,  when  united,  subquadrangular  in  form,  the 
width  being  about  three-fourths  of  the  length.  The  glabella  is  broadly 
conical,  rounded  in  front,  and  with  its  convex  surface  marked  by  two 
slightly  impressed  pairs  of  anterior  furrows,  and  a  pair  of  more  strongly 
marked  posterior  furrows  that  penetrate  obliquely  inward  to  a  shallow 


FOSSILS  OF  THE  CAMBRIAN. 


41 


transverse  furrow  that  unites  them;  occipital  ring  of  medium  width  and 
separated  from  the  glabella  by  a  well-defined,  but  not  deeply  impressed 
occipital  furrow;  dorsal  furrows  of  medium  strength  on  the  sides  of  the 
glabella  but  scarcely  shown  in  front;  fixed  cheeks  unusually  narrow  and 
rising  directly  up  to  the  large,  elongate  palpebral  lobes;  anteriorly  they 
slope  into  the  groove  of  the  frontal  limb;  posterior  extension  and  postero- 
lateral  limbs  unknown;  frontal  limb  between  the  glabella  and  furrow  nearly 
obsolete,  extending  beyond  the  furrow  as  a  broad  subspatulate,  somewhat 
convex  margin.  The  facial  suture  curves  a  little  outward  in  front  of  the 
eye  as  far  as  the  furrow  of  the  frontal  limb  and  then  recurves  inward  around 
to  the  front;  after  curving  around  the  large  eyelobe  to  near  the  posterior 
margin,  its  further  course  has  not  been  traced. 

Surface  smooth  or  slightly  punctate. 

Thorax  and  pygidium  unknown. 

Formation  and  localities. — Cambrian. ,  Prospect  Mountain  Group,  central 
portion  Secret  Canon  shale  in  New  York  Canon,  and  upper  layers  of  same 
on  north  side  of  the  canon  opposite  the  dump  of  the  shaft  of  the  Richmond 
mine,  Ruby  Hill,  Eureka  District,  Nevada. 


Dicellocephalus  Richmondensis,  n.  sp. 
Plate  x,  fig.  7. 

Glabella  and  fixed  cheeks,  united,  quadrangular  in  form,  the  width 
being  a  little  greater  than  the  length.  Glabella  elongate-subquadrangular, 
lateral  margins  slightly  converging  anteriorly,  and  with  the  front  a  little 
rounded;  length  and  breadth  as  three  to  four;  surface  moderately  convex, 
and  marked  by  a  slightly  impressed  posterior  pair  of  furrows,  directed 
obliquely  inward  two-thirds  the  distance  to  the  median  line,  and  two  pairs 
anterior  to  these  that  are  just  discernible  upon  the  smooth  surface;  occip- 
ital ring  of  medium  width,  distinct;  occipital  furrow  distinct,  but  not  deeply 
impressed;  dorsal  furrows  well  defined  at  the  sides  but  only  a  line  in  front 
of  the  glabella;  fixed  cheeks  broad,  rising  slightly  from  the  dorsal  furrows 
to  the  palpebral  lobes  and  sloping  away  before  and  behind  quite  rapidly; 
frontal  limb  rather  long  and  wide,  the  marginal  rim  broadly  arcuate,  the 


42  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

width  more  than  one-half  the  length  of  the  limb  between  it  and  the  glabella, 
somewhat  flattened  and  with  a  narrow  groove  between  it  and  the  depressed 
limb;  posterior  lateral  limbs  narrow,  marked  by  the  extension  of  the  occip- 
ital furrow  within  their  posterior  margin.  The  facial  sutures  cut  the 
frontal  rim  obliquely,  and  recurving  inward  pass  to  the  palpebral  lobes; 
curving  around  these  opposite  the  central  portion  of  the  glabella,  they  then 
extend  obliquely  outward  and  backward,  cutting  the  posterior  margin 
beyond  a  line  with  the  eyelobes. 

Surface  smooth  to  the  unaided  eye ;  minutely  punctate  under  a  strong 
magnifying  power. 

This  species  is  distinguished  by  its  broad  fixed  cheeks  and  long  frontal 
margin  with  the  flattened  rim. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  upper 
beds  of  the  Secret  Canon  shale,  on  the  opposite  side  of  the  cafion  from  the 
dump  of  the  shaft  of  the  Richmond  mine,  Ruby  Hill,  Eureka  District, 
Nevada. 

Dicellocephalus  f  angustifrons,  n.  sp. 
Plate  x,  figs.  1,  la  ft. 

Glabella  subquadrate;  width  at  the  base  equal  to  the  length,  but  nearly 
one-third  greater  than  the  width  of  the  anterior  margin ;  surface  moderately 
convex,  curving  down  in  front  and  marked  by  two  pairs  of  lightl}-  impressed 
glabellar  furrows  that  extend  obliquely  inward  one-third  the  distance  across 
the  glabella,  the  posterior  pair  nearly  separating  the  posterior  triangular 
lobes;  occipital  ring  rather  broad  and  distinctly  defined  by  a  strong  occip- 
ital furrow;  dorsal  furrows  narrow  but  strongly  impressed;  fixed  cheeks 
very  narrow  and  hardly  Separable  from  the  palpebral  lobes,  which  are  large, 
elongate,  and  situated  opposite  the  central  portion  of  the  glabella;  frontal 
limb  merely  a  line  between  the  glabella  and  the  rounded  rim;  lateral  limbs 
only  partly  known;  they  appear  to  be  narrow  and  rather  short. 

Associated  with  the  glabella  and  fixed  cheeks  are  numerous  free  cheeks 
that  undoubtedly  belong  to  this  species.  They  are  triangular  with  the 
upper  angle  truncated  to  form  the  base  of  the  eyelobe;  the  outer  margin 
is  strong,  somewhat  flattened,  and  separated  from  the  rapidly  ascending 
slope  to  the  furrow  at  the  base  of  the  eye  by  a  sharp  narrow  groove.  The 


FOSSILS  OF  THE  CAMBRIAN. 


43 


union  of  the  free  cheeks  with  the  fixed  cheeks  would  give  the  head  a  semicir- 
cular, strongly  convex  form,  with  rounded  postero-lateral  angles.  The 
pygidium  occurring  with  the  other  parts  is  transversely  elliptical,  about 
one-third  wider  than  long,  and  elevated  on  the  median  lobe;  the  frontal 
margin  is  broadly  rounded,  the  lateral  margins  scarcely  angular  at  the 
union  of  the  frontal  margin  and  the  more  sharply  rounded  posterior  line; 
axial  lobe  elevated,  convex,  about  one-half  the  length  of  the  pygidium,  and 
marked  by  six  transverse  rings,  including  the  terminal  one;  lateral  lobes 
broad,  sloping  rapidly  away  from  the  axial  lobe  and  then  spreading  out  in 
a  broad,  flattened  border;  their  surface  is  marked  by  three  broad  anchy- 
losed  segments,  besides  the  narrow  anterior  articulating  projection  and  the 
broad  posterior  termination. 

Surface  of  the  head  finely  granulose,  and  the  pygidium  the  same,  with 
the  exception  of  the  irregular  striae  on  the  border,  the  latter  are  sub- 
parallel  to  the  margin. 

This  species  in  the  general  form  of  the  head  and  pygidium  resembles 
many  species  referred  by  Mr.  Billings  to  his  genus  Bathyurus,  but  it. is 
nearer  Dicellocephalus,  if  we  compare  it  with  typical  forms  of  the  genus 
from  the  Potsdam  sandstone  of  Wisconsin,  and  is  referred  to  that  genus 
provisionally. 

Formation  and  localities.— Cambrian.  Prospect  Mountain  Group. 
Summit  of  Hamburg  shale,  on  the  ridge  north  of  the  Dunderberg  mine, 
and  in  a  matrix  of  a  similar  character  at  the  southeast  base  of  Lookout 
Mountain,  Sierra  Canon,  Eureka  District,  Nevada. 


Dicellocephalus  lole,  n.  sp. 
Plate  x,  fig.  19. 

Glabella  subquadrate,  length  exclusive  of  the  occipital  ring  equal  to 
the  width  at  the  base;  it  narrows  a  trifle  anteriorly,  is  transverse  in  front, 
and  has  its  lateral  angles  rounded;  surface  gently  convex,  rounding  down- 
ward in  front,  and  marked  by  two  pairs  of  rather  strong,  but  not  deeply 
impressed,  furrows  that  extend  obliquely  inward  well  towards  the  median 
line. 


44  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Occipital  ring  narrow,  flattened;  occipital  furrow  very  shallow;  fixed 
cheeks  narrow,  separated  from  the  glabella  by  distinctly  marked  dorsal 
furrows,  and  sloping  rapidly  from  the  palpebral  lobes  before  and  behind; 
palpebral  lobes  elongate,  slightly  sinuate,  and  with  a  groove  within  the 
margin ;  frontal  limb  broad,  rather  short,  sloping  down  to  a  line  or  groove 
beyond  which  the  flattened  margin  extends,  the  width  of  the  margin  nearly 
equaling  the  distance  between  it  and  the  glabella;  postero-lateral  limits  of 
medium  width,  with  the  extension  of  the  occipital  furrow  marking  their 
posterior  portion ;  their  lateral  extension  is  a  little  greater  than  one-half  the 
length  of  the  head. 

Facial  suture  directed  outward  from  in  front  of  the  eyelobe  to  the 
anterior  rim  of  the  head,  around  which  it  abruptly  curves,  terminating  at 
the  front  margin;  behind  the  eye  it  passes  obliquely  backward  at  an  angle 
of  25°  with  the  posterior  margin  of  the  head,  cutting  the  latter  at  a  distance 
from  the  dorsal  furrow  equal  to  the  width  of  the  anterior  end  of  the  glabella. 

Surface  finely  granulose  under  a  strong  magnifying  glass. 

Thorax  and  pygidium  unknown.  One  associated  pygidium  is  much 
like  that  illustrated  by  Hall  and  Whitfield,  Geol.  Expl.  Fortieth  Par.,  vol. 
iv,  pi.  i,  fig.  39. 

Formation  and  locality. — Cambrian.  Upper  portion  of  Prospect  Mount- 
ain Group,  near  the  Bullwhacker  mine,  Eureka  District,  Nevada. 

Dicellocephalus  Marica,  n.  sp. 
Plate  x,  fig.  13. 

Glabella  and  fixed  cheeks  subquadrate  in  outline,  narrowing  somewhat 
towards  the  front.  Glabella  subquadrangular  and  almost  squarely  truncate 
in  front,  which  is  not  quite  as  wide  as  the  base;  strongly  convex,  and 
marked  by  three  pairs  of  furrows,  the  two  anterior  pair  but  slightly  im- 
pressed and  very  short;  the  posterior  pair  extend  obliquely  inward  one- 
third  the  distance  across  from  each  side,  and  are  united  by  a  slight  trans- 
verse furrow;  occipital  ring  strong  and  elevated;  occipital  furrow  well 
defined;  dorsal  furrows  strongly  impressed;  fixed  cheeks  moderately  convex, 
narrow  in  front,  widening  at  the  palpebral  lobes,  and  sloping  away  rapidly 
in  front,  and  less  so  back  of  the  eyelobes;  eyelobes  narrow,  semicircular, 


FOSSILS  OF  THE  CAMBRIAN. 


45 


and  situated  opposite  the  central  portion  of  the  glabella;  frontal  limb 
obsolete  except  the  round,  thick,  marginal  rim  just  in  advance  of  the 
glabella;  the  posterior  limbs  are  broken  away  at  a  little  distance  from  the 
dorsal  furrows. 

Surface,  as  seen  under  a  strong  magnifying  glass,  with  fine  inoscu- 
lating, flattened  lines  surrounding  minute  round  or  irregularly  oval  spaces. 

Formation  and  locality. — Upper  beds  of  the  Cambrian  just  south  of  the 
Hamburg  mine,  and  in  the  same  canon,  Eureka  District,  Nevada. 

Dicellocephalus  ?  quadriceps  H.  &  W. 
Plate  ix,  fig.  24. 

Dikelloceplialus  f  quadriceps  Hall  &  Whitfield,  1879.    Geol.  Expl.  Fortieth  Parallel,  voL 
iv,  p.  240,  pi.  i.,  figs.  37-40. 

Type  specimens  from  the  base  of  Ute  peak,  Wahsatch  Eange,  Utah. 

A  careful  comparison  of  the  Wahsatch  specimens  with  those  from 
Nevada  fails  to  give  sufficient  specific  distinction  to  separate  them  on  the 
evidence  afforded  by  the  material  at  hand.  A  small  glabella  with  portions 
of  the  fixed  cheeks  attached  is  figured  on  plate  ix,  fig.  23,  to  show  the 
peculiar  form  of  the  glabella  and  the  disappearance  of  the  very  faint 
glabellar  furrows,  scarcely  shown  in  the  specimens  from  Utah;  this  repre- 
sents one  extreme  of  the  species,  while  the  specimen  illustrated  in  the 
Paleontology  of  the  Geological  Exploration  of  the  Fortieth  Parallel  exhibits 
the  other,  or  more  mature  form. 

The  generic  reference  is  open  to  question,  but  with  our  present  material 
little  more  can  be  done  with  it. 

Formation  and  localities. — Cambrian.  Prospect  Mountain  Group,  base 
of  Secret  Canon  shale,  New  York  Canon,  and  in  Cambrian  limestone  on 
the  west  side  of  the  Eureka  District  on  the  Antelope  Valley  slope,  near  the 
plain,  Eureka  District,  Nevada. 

Dicellocephalus  ?  expausus,  n.  sp. 
Plate  ix,  fig.  19. 

Glabella  elongate  subquadrangular,  or  subclavate,  the  base  about  one- 
fifth  narrower  than  the  front;  surface  convex  and  without  perceptible  fur- 


46  PALEONTOLOGY  OF  THE  EUBEKA  DISTEIOT. 

rows;  occipital  furrow  distinctly  defined;  occipital  ring  strong,  with  a  small 
spine  on  the  center  of  the  posterior  portion ;  dorsal  furrows  well  defined 
along  the  sides  of  the  glabella;  fixed  cheeks  of  medium  width,  palpebral 
lobes  unknown ;  an  ocular  (?)  ridge  crosses  the  anterior  portion  of  the 
right  fixed  cheek,  so  as  to  indicate  a  moderate  sized  eyelobe  between  it  and 
the  postero-lateral  limb;  frontal  limb  as  a  narrow  rim;  postero-lateral  limbs 
rather  narrow,  extended  and  marked  by  a  strong  furrow  within  the  poste- 
rior margin. 

Surface  finely  punctate. 

This  species  and  the  preceding  are  closely  related,  judging  from  the 
parts  which  we  have  for  comparison.  It  is  hoped  that  in  some  more  favor- 
able locality  entire  specimens  may  be  obtained  of  these  and  the  many  other 
species  known  only  by  fragments,  so  that  the  generic  characters  can  be 
determined  with  greater  certainty  and  more  positive  specific  references 
made. 

Formation  and  localities. — Cambrian.  Prospect  Mountain  limestone  at 
base  of  Secret  Cafion  shale,  in  New  York  Cafion,  and  also  in  a  small  expos- 
ure of  Cambrian  limestone  on  the  west  side  of  the  Mahogany  Hills,  in 
Antelope  Valley,  Eureka  District,  Nevada. 

Genus  PTYCHOPAEIA  Corda.8 

Ftychoparia  (?)  Prospectenals,  n.  sp. 
Plate  ix,  fig.  20. 

The  general  outline  of  the  head  is  moderately  convex,  semicircular, 
the  width  being  about  twice  the  length. 

The  glabella  is  sub  conical,  truncate  in  front  and  marked  by  three  pairs 
of  short,  slightly  impressed  glabellar  furrows;  occipital  ring  distinctly  de- 
fined by  a  narrow,  lightly  impressed  occipital  furrow;  fixed  cheeks  broad, 
of  equal  elevation  with  the  glabella,  and  extending  beyond  it  anteriorly, 
the  space  between  them  on  the  broad  frontal  limb  being  taken  by  a  small 

6 The  reason  for  using  the  generic  term  Ptychoparia  rather  than  Crepicephalus,  as  used  by 
Messrs.  Hall  and  Whitfield  in  the  Paleontology  of  the  Fortieth  Parallel  Exploring  Expedition,  is  given 
in  a  bulletin  of  the  Geological  Survey  now  ready  for  the  press,  entitled  a  "Review  of  the  Fauna  of  the 
St.  John  Formation."  The  relations  of  the  genera  Conocoryphe,  Ptychoparia,  Crepicephalus,  Soleno- 
pleura,  Liostracus,  and  Conocephalites  are  mentioned. — C.  D.  W. 


FOSSILS  OF  THE  CAMBRIAN. 


47 


swelling  or  boss  that,  but  for  the  slight  transverse  dorsal  furrow  between  it 
and  the  glabella,  might  be  mistaken  for  a  continuation  of  the  latter;  the 
eyelobes  are  comparatively  large  for  a  species  of  this  character  and  occupy 
a  prominent  position  on  the  outer  margin  of  the  cheeks,  a  distinct  ocular 
ridge  crossing  the  latter  from  the  anterior  margin  of  the  eyes  to  the  dorsal 
furrow  on  a  line  with  the  front  of  the  glabella;  the  lateral  limbs  are  narrow, 
rather  short,  and , slope  rapidly  downward  back  of  the  eyelobes;  frontal 
limb  broad  at  the  center,  narrowing  in  front  of  the  fixed  cheeks  and  bor- 
dered anteriorly  by  a  not  very  distinctly  defined  rounded  margin.  The 
facial  suture  curves  a  little  inward  in  front  of  the  eye  and  appears  to  ter- 
minate on  the  front  line  somewhat  in  advance  of  a  line  passing  through  the 
center  of  the  tubercle  in  front  of  the  glabella ;  behind  the  eye  it  extends 
obliquely  outward  and  backward  to  the  posterior  margin  of  the  head,  out- 
lining an  elongate  triangular  postero-lateral  limb. 

Under  a  strong  magnifying  power  the  surface  is  seen  to  be  finely  gran- 
ulose. 

Free  cheeks,  thorax,  and  pygidium  unknown. 

Formation  and  locality. — Cambrian.  Mountain  shale  band  of  the  Pros- 
pect Mountain  Group,  on  the  east  slope  of  Prospect  Peak,  Eureka  District, 
Nevada. 

Ptychoparia  (?)  Linnarssoni,  n.  sp. 
Plate  ix,  figs.  18,  18  a. 

The  glabella  and  fixed  cheeks  are  the  only  portions  of  this  interesting 
species  that  have  been  identified.  The  glabella  is  small  in  proportion  to 
the  area  occupied  by  the  cheeks  and  frontal  limb;  it  is  conical  in  form, 
truncate  in  front,  moderately  convex,  and  marked  by  three  pairs  of  very 
short,  slightly  impressed  glabellar  furrows;  the  latter  only  observed  on  very 
perfect  specimens;  occipital  ring  narrow,  as  also  the  shallow  occipital  fur- 
row ;  fixed  cheeks  broad,  elevated,  and  projecting  forward  on  to  the  frontal 
limb  considerably  in  advance  of  the  front  of  the  glabella,  the  included 
space  between  their  anterior  portions  being  occupied  by  an  elongate  oval 
boss  th&t  is  separated  from  the  glabella  by  a  rather  broad,  shallow  furrow; 
the  boss  or  tubercle  extends  to  the  rounded  thick  frontal  rim,  from  which  it 


48  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

is  defined  by  a  scarcely  perceptible  depression;  dorsal  furrows  broad,  well 
defined,  and  running  out  in  front  much  broader  between  the  tubercle  and 
the  fixed  cheeks;  palpebral  lobes  rather  prominent  and  situated  opposite 
the  anterior  end  of  the  glabella;  postero-lateral  limbs  long,  triangular,  and 
marked  by  a  strong  furrow  within  their  posterior  margin.  Facial  suture 
directed  forward  in  front  of  the  eyelobes,  curving  outward  a  trifle  and  then 
a  little  inward  on  the  frontal  limb,  around  the  front  of  which  it  does  not 
appear  to  extend;  back  of  the  eyelobe  it  extends  obliquely  outward  and 
backward,  bending  a  little  more  abruptly  backward  towards  the  lateral  ex- 
tension of  the  limb,  terminating  at  or  just  within  the  genal  angle  at  a  dis- 
tance from  the  dorsal  furrow  equal  in  one  example  to  the  entire  length,  and 
in  another  to  two-thirds  of  the  length  of  the  head. 

Surface  minutely  granulose. 

The  specific  name  is  given  in  honor  of  Dr.  G.  Linnarsson,  the  eminent 
Swedish  paleontologist. 

This  species  is  allied  to  P.  Prospectensis,  but  differs  in  the  position  of 
the  eyelobes  and  the  larger  frontal  limb,  changes,  however,  that  may  be 
only  varietal,  as  there  is  an  interval  of  3,000  feet  of  strata  between  the 
horizons  at  which  they  respectively  occur,  but  for  the  present  they  are 
regarded  as  distinct  species.  They  are  strongly  marked  forms  and  types  of 
a  group  of  the  genus  not  specially  recognized  heretofore,  as  they  unite  the 
presence  of  a  tuberosity  in  front  of  the  glabella,  seen  only  (with  the  excep- 
tion of  Ptyclioparia  calymenoides  Whitfield)  in  the  eyeless  trilobites,  Cono- 
coryphe  coronatus  Barr.,  C.  exsulans  Linnarsson,  C.  Matthewi  Hartt,  C.  Solvensis 
Hicks,  C.  (Elyx)  laticeps  Angelin,  with  the  presence  of  fully-developed  eyes 
and  the  direction  of  the  facial  sutures  as  in  Ptyclioparia  striatus,  etc.  I  am 
not  at  all  certain  that  P.  calymenoides  should  be  included  with  them,  as  the 
tuberosity  in  that  species  may  be  only  an  unusual  thickening  of  the  frontal 
rim  of  the  head  and  not  the  true  frontal  limb,  a  question  not  readity  deter- 
mined with  the  specimens  thus  far  obtained 

Formation  and  locality.—  Cambrian.  Prospect  Mountain  Group,  in  the 
upper  beds  of  the  Secret  Canon  shale,  on  the  east  side  of  Secret  Canon, 
opposite  the  Geddes  and  Bertrand  mine,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CAMBRIAN. 


49 


Ptychoparia  (Solenopleura?)  breviceps,  n.  sp. 
Plate  x,  fig.  9. 

Head  rather  small,  convex,  semicircular;  length  a  little  less  than  one- 
half  the  width  of  the  posterior  margin.  Glabella  large,  prominent;  length 
and  width  at  the  base  nearly  equal,  converging  rapidly  towards  the  trun- 
cated front  to  three-fifths  the  width  of  the  base;  the  posterior  glabellar 
furrow  extends  entirely  across,  while  the  two  anterior  pairs  are  scarcely 
discernible;  occipital  ring  transverse,  rounded,  separated  from  the  glabella 
by  a  strong,  rounded  furrow,  and  extending  laterally  as  the  narrow  rounded 
posterior  border  of  the  head ;  dorsal  furrows  strongly  defined  ;  fixed  cheeks 
convex,  depressed  below  the  level  of  the  glabella,  rather  wide  and  sloping 
abruptly  to  the  frontal  border,  slightly  depressed  towards  the  small  palpe- 
bral  lobes  and  sloping  away  rapidly  posteriorly;  ocular  ridges  strongly 
marked,  trending  obliquely  backward  from  the  antero-lateral  angles  of  the 
glabella;  postero-lateral  limbs  rather  narrow,  distinctly  grooved  on  the 
posterior  edges  by  the  occipital  furrows;  frontal  limb  obsolete,  the  strong, 
rounded,  marginal  border  touching  the  anterior  margin  of  the  glabella. 
Facial  suture  curves  slightly  inward  in  its  course  from  the  eyelobe  to  the 
front  margin  of  the  head,  and  apparently  cuts  obliquely  inward  across  the 
frontal  rim ;  behind  the  eye  it  is  directed  outward,  curving  a  little  backward 
to  the  posterior  margin  and  outlining  an  elongate  triangular  lateral  limb. 

Surface  apparently  smooth  or  very  finely  punctate. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  in  the 
Hamburg  shale  belt  north  of  Adams  Hill,  Eureka  District,  Nevada. 


Ptychoparia  (?)  pernasutus,  n.  sp. 
Plate  x,  figs.  8,  8  a-b. 

Entire  form  unknown.  The  glabella  and  fixed  cheeks,  and  the  free 
cheeks  associated  with  them,  give  the  head  a  rounded,  subtriangular  form; 
it  is  strongly  convex  and  produced  anteriorly  in  a  strong,  elongate,  flattened 
triangular  process,  the  anterior  third  of  which  bends  downward  with  a  uni- 
form curvature;  the  width  of  the  process  at  the  base  is  about  two-thirds  of 
4  o  D  w 


50  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

its  length  from  the  marginal  furrow;    laterally  it  passes   into   the  strong- 
rounded  border  of  which  it  is  an  extension. 

Glabella  strongly  convex,  broadly  conical  in  outline  and  rounded 
truncate  in  front;  the  greatest  breadth  near  the  base  is  five-sixths  of  the 
length  from  the  occipital  furrow  to  the  front;  three  pairs  of  furrows  divide  it 
into  three  posterior  subequal  lobes  and  one  smaller  anterior  lobe;  the  poste- 
rior furrows  penetrate  obliquely  backward  nearly  two-thirds  the  distance  to 
the  median  line,  while  the  two  anterior  pairs  are  short  and  but  slightly  im- 
pressed; occipital  furrow  broad  and  well  defined,  with  a  small  triangular- 
shaped  node  at  each  postero-lateral^  angle  of  the  glabella;  occipital  ring 
strong  and  narrowing  towards  the  dorsal  furrows.  Only  small  portions  of 
the  fixed  cheeks  are  preserved;  these  show  the  presence  of  strongly-defined 
dorsal  furrows  around  the  glabella,  and  that  the  cheeks  sloped  up  rapidly 
from  them  towards  the  palpebral  lobes,  which,  from  the  associated  free 
cheek,  must  have  been  of  rather  large  size  and  not  far  from  the  glabella, 
giving  a  somewhat  narrow  fixed  cheek;  the  anterior  limb  has  a  length  of 
about  one-fifth  of  that  of  the  glabella  from  the  occipital  furrow,  it  is  slightly 
convex  and  slopes  into  the  rather  strong  furrow  between  it  and  the  nasute-- 
like  extension  of  the  marginal  border,  its  anterior  margin  forming  an  obtuse 
angle  at  the  median  line. 

The  associated  free  cheek  is  subtriangular  in  outline,  strongly  convex, 
with  a  wide,  strong  marginal  border  and  groove,  and  a  spinous  extension 
of  the  genal  angle,  with  the  anterior  margin  extended  beyond  the  union  of 
the  cheek  with  the  margin,  the  interior  angle  is  hollowed  out  for  the  recep- 
tion of  a  large  eyelobe. 

Surface  granulose  and  probably  pustulose  on  the  glabella. 

This  is  a  large  and  unusually  striking  species.  In  the  extension  of  the 
frontal  border  it  is  like  Anomocare  acuminatum  Angelin,  a  feature  not  here- 
tofore observed  in  any  American  species  from  this  horizon. 

Formation  and  locality. — Summit  of  the  Cambrian,  Prospect  Mountain 
Group,  east  side  of  the  canon  east  of  the  Hamburg  Ridge,  Eureka  Dis- 
trict, Nevada. 


FOSSILS  OF  THE  CAMBRIAN. 


51 


Ptychoparia  (Euloma  ?)  dissimilis,  n.  sp. 
Plate  ix,  fig.  28. 

Glabella  prominent,  strongly  convex,  the  anterior  lobe  curving-  down- 
ward and  under  to  the  frontal  margin;  length  and  width  at  the  base  equal; 
marked  by  two  pairs  of  glabellar  furrows  extending  obliquely  inward,  the 
posterior  pair  nearly  cutting  off  the  triangular-shaped  posterior  lobes ;  occip- 
ital ring  broad  at  the  center,  narrowing  laterally ;  occipital  furrows  strongly 
impressed,  as  are  the  dorsal  furrows  along  the  sides  of  the  central  and  pos- 
terior portions  of  the  glabella;  fixed  cheeks  very  narrow;  palpebral  lobes 
large,  moderately  elongate,  slightly  sinuous,  with  a  strong  groove  within 
the  margin;  frontal  lobe  a  narrow  rounded  rim;  postero-lateral  limbs  un- 
known. 

This  species  is  known  only  by  the  parts  mentioned.  It  is  allied  to 
Ptychoparia  Eos  Hall,  and  a  somewhat  similar  form  has  been  described  as 
Menocephalus  Sedgwlcki  Billings.  They  appear  to  form  a  small  group  of 
the  Conocephalidye,  the  limits  of  which  have  not  been  defined.  The  refer- 
ence to  the  genus  Menocephalus  is  of  doubtful  propriety,  since,  up  to  the 
present  time,  the  fragment  referred  to  as  the  type  by  Owen  has  never  again 
been  even  generically  or  specifically  recognized  in  all  the  great  collections 
from  the  Potsdam  sandstone  of  the  Wisconsin  and  Minnesota,  and  it  appears 
to  be  practically  impossible  to  identify  it.  The  two  species  referred  to  the 
genus  by  Billings,  Palaeozoic  Fossils,  vol.  i,  p.  407,  and  Geology  of  Canada, 
p.  237,  also  appear  to  belong  to  two  distinct  genera. 

Formation  and  locality. — Cambrian.  Secret  Canon  shale  of  the  Prospect 
Mountain  Group,  New  York  Canon,  Eureka  District,  Nevada. 


Ptychoparia  occidentalis,  n.  sp. 
Plate  x,  fig.  5. 

Head  within  the  facial  sutures,  exclusive  of  the  postero-lateral  limbs, 
quadrangular  in  form;  glabella  subconical,  the  sides  slightly  converging 
towards  the  rounded  front;  surface  uniformly  convex  and  marked  by  three 
pairs  of  moderately  oblique  glabellar  furrows,  the  two  posterior  pairs  of 


52  PALEONTOLOGY  OF  THE  EDEEKA  DISTRICT. 

which  are  more  strongly  impressed  and  reach  two-thirds  the  distance  to  the 
median  line,  the  anterior  pair  are  short  and  faintly  defined;  occipital  furrow 
distinct;  occipital  ring  rounded  and  rather  under  the  medium  size;  dorsal 
furrows  well  impressed  on  the  sides  and  in  front  of  the  glabella;  fixed 
cheeks  of  medium  width,  not  very  convex,  and  sloping  away  gradually  in 
front  and  behind;  ocular  ridges  well  marked;  frontal  limb  extended  a  little 
beyond  the  fixed  cheeks,  slightly  convex,  and  bordered  by  a  flattened  rim 
that  is  two-thirds  as  wide  as  the  width  between  it  and  the  glabella;  eye- 
lobes  of  medium  size;  postero-lateral  limbs  narrow,  extended,  with  a 
strongly  marked  continuation  of  the  occipital  furrow  just  within  their  pos- 
terior margin.  The  facial  suture  cuts  very  obliquely  across  the  frontal  rim 
of  the  head  and  abruptly  recurving  inward  at  its  interior  margin  passes 
slightly  inward  in  a  direct  line  to  the  eyelobe,  back  of  which  it  is  directed 
outward  with  a  backward  curve  on  the  outer  third  of  the  lateral  limb,  to  the 
posterior  margin  of  the  head,  which  it  cuts  at  a  distance  from  the  dorsal  furrow 
equal  to  the  width  of  the  base  of  the  glabella. 

Surface  of  head  finely  granulose;  striate  on  the  frontal  limb. 

In  the  general  outline  of  the  facial  sutures  this  species  might  be  referred 
to  Dicellocephalus,  but  the  glabella  is  of  the  true  type  of  Ptychoparia,  and 
the  other  parts  are  not  incompatible  with  a  reference  to  that  genus. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  at  the 
base  of  the  Secret  Canon  shale  on  the  west  side  of  Secret  Canon,  Eureka 
District,  Nevada. 

Ptychoparia  similis,  n.  sp. 
Plate  x,  fig.  10. 

The  glabella  and  fixed  cheeks  form  a  subquadrangular  outline,  with  the 
central  portion,  opposite  the  eyes,  arching  inward,  the  frontal  and  postero-lat- 
eral limbs  terminating  the  angles ;  glabella  broadly  conical,  sides  straight, 
converging  slightly  anteriorly  to  the  rounded  frontal  margin;  surface  strongly 
convex  and  broken  by  three  pairs  of  furrows,  the  anterior  of  which  are  very 
faint,  the  middle  pair  somewhat  stronger  and  the  posterior  still  more  so;  all 
are  deflected  a  little  backward,  the  posterior  pair  strongly  outlining  the  pos- 
terior lobes;  occipital  ring  strong  and  full  and  separated  by  a  deeply  im- 


FOSSILS  OF  THE  CAMBRIAN. 


53 


pressed  occipital  furrow;  dorsal  furrows  distinct  at  the  front  and  sides  of  the 
glabella;  fixed  cheeks  narrow  and  rising  rapidly  from  the  dorsal  furrows  to 
the  palpebral  lobes,  sloping  away  somewhat  abruptly  to  the  front  and  back; 
frontal  limb  short  and  broad,  convex,  and  sloping  quite  rapidly  to  the  slight 
furrow  within  the  broad,  plauulate  margin,  which  appears  to  be  a  continua- 
tion of  it;  postero-lateral  limbs  narrow,  posterior  margins  rather  strong, 
with  a  narrow  groove  within. 

Surface  of  the  glabella  finely  pustulose. 

This  species  is  allied  to  P.  Montanensis  Whitfield,  but  differs  in  the 
character  of  the  frontal  limb  very  decidedly,  as  also  in  the  planulate  margin. 
Some  of  the  examples  show  the  front  margin  cut  away  by  the  suture  line 
which  crosses  it  obliquely  from  about  one-third  the  distance  from  the  center, 
at  its  front  margin,  to  the  postero-lateral  angle. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  in  the 
upper  beds  of  the  Secret  Canon  shale  across  the  canon  opposite  the 
northeast  dump  of  the  Richmond  mine  shaft,  Ruby  Hill,  Eureka  District, 
Nevada. 

Ftychoparia  similis,  var.  robustus,  n.  var. 
Plate  i,  figa.  9,  9  a. 

Glabella  and  fixed  cheeks  subquadrangular  in  outline.  Glabella  ob- 
tusely conical,  sides  slightly  converging  to  the  rounded  front;  surface 
convex,  marked  by  two  pairs  of  rather  short,  slightly  impressed,  oblique 
furrows;  occipital  ring  strong,  with  a  well-defined  occipital  furrow;  dorsal 
furrows  well  defined  in  front  and  at  the  sides  of  the  glabella ;  fixed  cheeks 
narrow,  rising  rather  rapidly  from  the  dorsal  furrows  up  to  the  front  of  the 
small  palpebral  lobe  and  then  arching  over  to  unite  with  the  short,  rounded 
frontal  limb ;  ocular  ridges  well  marked ;  frontal  margin  rather  broad  and 
flat ;  postero-lateral  limbs  narrow  as  in  P.  similis.  Surface  of  the  glabella 
and  postero-lateral  limbs  finely  pustulose. 

This  species,  in  the  parts  preserved,  is  closely  allied  to  P.  similis.  The 
glabella  is  shorter,  more  convex,  and  nearly  as  broad  as  long,  while  that  of 
P.  similis  is  one-fourth  longer  than  broad  The  entire  appearance  gives  the 
idea  of  its  being  a  robust  form  of  P.  similis. 

Formation  and  locality. — Same  as  Ptychoparia,  similis. 


54  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Ptychoparia  (Euloina  ?)  affinis,  n.  sp. 
Plate  x,  fig.  12. 

General  form  and  appearance  much  like  that  of  P.  similis,  but  differing 
in  its  more  pronounced  convexity,  in  the  more  deeply  impressed  two  poste- 
rior pairs  of  glabellar  furrows  and  the  rounded  marginal  rim  instead  of  the 
long  planulate  margin  ;  features  that  render  the  two  very  distinct.  Surface 
finely  pustulose.  Mr.  E.  Billings  has  described  an  allied  form  from  Canada 
as  Menocephalus  Sedgwicki,  the  generic  reference  of  which  is  very  doubtful. 

Formations  and  localities. — Cambrian  and  Silurian.  In  the  limestones  or 
passage  beds  between  the  Prospect  Mountain  and  Pogonip  Groups  above 
the  Hamburg  belt  of  shale  east  of  the  Hamburg  mine,  and  in  the  lime- 
stone of  a  little  higher  horizon  northeast  of  Adams  Hill,  Eureka  District, 
Nevada. 

Ptychoparia  laeviceps,  n.  sp. 
Plate  x,  figs.  17,  18. 

General  form  of  head  within  the  facial  sutures  subtrapezoidal.  Glabella 
conical,  strongly  convex,  with  very  faintly  defined  dorsal  furrows  separat- 
ing- it  from  the  rapidly  sloping  fixed  cheeks ;  two  pairs  of  furrows  are  just 
discernible  by  slight  impressions  on  the  surface ;  occipital  ring  strong, 
rounded,  separated  from  the  glabella  by  a  shallow  furrow ;  fixed  cheeks  of 
medium  width,  sloping  rapidly  down  from  the  glabella  and  from  the  small 
eyelobe,  situated  a  little  back  of  the  center,  to  the  front  and  back;  frontal 
limb  short,' convex,  and  depressed  to  the  broadly  rounded,  strong,  marginal 
rim;  postero-lateral  limbs  rather  strong  and  running  out  beyond  the  line  of 
the  lateral  extension  of  the  frontal  limb. 

Surface  smooth  to  the  unaided  eye ;  under  a  strong  magnifying  power, 
minutely  granulose. 

This  species  is  peculiar  in  the  absence  of  strongly  marked  furrows  and 
the  general  smooth  appearance,  as  though  all  strong  outlines  had  been 
removed  by  rubbing  off  the  outer  surfaces.  In  form  it  resembles  the  follow- 
ing species  and  is  closely  allied  to  it.  It  differs  from  it  in  the  general  ap- 
pearance and  also  in  the  course  of  the  facial  sutures  in  front  of  the  eyes. 


FOSSILS  OF  THE  CAMBRIAN. 


f>5 


Formation  and  locality. — Cambrian.  Prospect  Mountain  Group,  upper 
beds  of  the  Secret  Canon  shale  on  the  east  side  of  Secret  Canon,  Eureka 
District,  Nevada. 

Ptychoparia  Oweni  M.  &  H. 
Plate  x,  tigs.  3,  .5  a. 

Arionelliis  (Crepicephalus)  Oiceni  Meek  &  Hayden,  186L.  Proc.  Acad.  Nat.  Sci.  Philad., 
vol.  xiii,  p.  430. 

Ariondlua  ?  Oweni  Meek  &  Ilu.ulen,  1802.  Amer.  Jour.  Sci.,  2d  Series,  vol.  xxxiii, 
p.  74. 

Agraulos  Oweni  Meek  &  Hayden,  1804.     Pal.  Upper  Missouri,  p.  9,  figs.  A,  B,  C. 

Agraulos  t  Meek  &  Hayden,  1804.     Pal.  Upper  Missouri,  p.  10,  pi.  i,  fig.  4. 

Conocoryphe  (Ptychoparia)  Gallatinentsis  Meek,  1873.  Sixth  Ann.  Rep.  U.  S.  Geol.  Surv. 
Territories,  for  the  year  1872,  p.  485. 

Crepicephalus  (Loganellus)  central-is  Whitfield,  1877.  Prelim.  Rep.  Pal.  Black  Hills, 
p.  10. 

Crepicephalus  contrails  Whitfield,  1881.  Rep.  Geol.  and  Resources  Black  Hills  of  Da- 
kota, p.  341,  pi.  ii,  figs.  21,  24. 

I  was  somewhat  surprised  on  bringing  together  the  types  of  Arionellus 
•=  Ptychoparia  Oweni,  Conocoryphe  =  Ptychoparia  Gallatinensis,  and  Crepi- 
cephalus =  Ptychoparia  centralis,  to  find  that  they  were  representatives  of  one 
somewhat  variable  species.  The  types  of  P.  Oweni  and  P.  centralis  are  abso- 
lutely identical,  while  P.  Gallatinensis  is  only  a  variety  of  P.  Oweni  that 
shows  a  wider  range  of  variation,  owing  to  the  fact  that  we  have  a  larger  series 
of  specimens  representing  it.  One  of  these  variations  is  shown  in  the  Black 

Hills  specimen  figured  by.  Meek  and  Hayden  as  Agraulos  f ,  and 

labeled  (probably  by  Mr.  Meek)  in  the  collection  of  the  Smithsonian  Insti- 
tution as  Conocephalites  sp.  ? 

The  Nevada  species  is  the  same  as  that  from  the  Gallatin  River,  Mon- 
tana, and  the  Black  Hills  of  Dakota.  It  presents  much  the  same  variations 
in  size,  and  the  presence  or  absence  of  the  glabellar  furrows  is  a  noticeable 
feature  in  each.  Some  of  the  younger  specimens  resemble  Conocephalites  = 
Ptyclioparia  arenosus  Bill.,  from  the  Potsdam  sandstone  of  Vermont,  but  dif- 
fer in  the  width  of  the  fixed  cheeks  and  frontal  limb. 

P.  Oweni  ranges  through  nearly  4,000  feet  of  strata,  being  found  in  the 
Prospect  Mountain  limestone  of  the  700-foot  level  of  the  Richmond  mine 
and  well  up  in  the  Pogonip  Group  on  the  ridge  east  of  the  Hamburg  mine, 


56  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

and  at  various  horizons  between  the  two  in  New  York,  Secret,  and  Sierra 
Canons,  and  on  the  Hamburg  Ridge.  In  the  Black  Hills  it  occurs  at 
about  the  horizon  of  the  upper  portion  of  the  Prospect  Mountain  Group  of 
the  Eureka  District,  Nevada. 

In  a  report  on  the  Cambrian  fauna  of  the  United  States,  now  in  course 
of  preparation,  the  types  of  the  various  species  given  in  the  synonymy  of 
Ptychop&ria  Oweni  will  be  illustrated 

Ptychoparia  Anytus  H.  &  W. 
Plate  ix,  fig.  26. 

Crepicephahts  (LocjaneUiis]  nnytus  Hall  &  Whitfield,  1877.  Geol.  Expl.  Fortieth  Par., 
vol.  iv,  p  219,  pi.  ii,  figs.  19-21. 

Compare  Crepicephalus=Plychoparia  planus  Whitfield,  1877.  Geology  and  Resources 
of  the  Black  Hills  of  Dakota,  p.  341,  pi.  ii,  figs.  21-24.  Also  Crepicephalus 
(L.)  =  Ptychoparia  Montanensin  Whitfield,  1876.  Rep.  Recon.  Carroll, 
Montana,  to  Yellowstone  Kat.  Park,  Lndlow,  p.  141,  pi.  i,  figs.  1,  2. 

The  specimen  illustrated  by  fig  26  of  plate  ix,  differs  from  the  type  of 
P.  Anytus  in  having  a  somewhat  narrower,  more  quadrilateral  glabella, 
and  also  a  thicker  anterior  rim  to  the  head,  but  on  comparing  several  spe- 
cimens with  the  typical  specimens  from  Schell  Creek,  Nevada,  these  varia- 
tions are  seen  in  each  series,  and  no  satisfactory  differences  remain  upon 
which  to  base  a  distinct  species.  The  figure  given  by  Messrs.  Hall  and 
Whitfield  shows  a  larger,  broader,  and  more  conical  glabella  in  proportion 
to  the  head  than  that  of  fig.  26,  plate  ix,  of  this  report,  the  two  figures  in 
the  two  reports  giving  the  range  of  variation  in  the  head  as  far  as  known. 

On  comparing  the  type  of  P.  planus  Whitfield,  with  a  head  of  P.  Anytus, 
broken  just  as  the  type  of  P.  planus  is,  there  does  not  appear  to  be  the 
slightest  difference  between  the  two.  We  labor,  however,  under  the  dis- 
advantage of  comparing  with  a  cast  of  a  fragment  of  the  head  as  the  origi- 
nal type,  and  cannot  decide  positively  until  more  and  better  material  is 
collected  from  the  original  locality. 

P.  Montancnsis  is  a  closely  allied  species  of  which  we  have  not  seen 
the  original  type. 

Formation  and  locality. — Cambrian.  In  the  upper  beds  of  the  Secret 
Canon  shale,  on  the  east  side  of  New  York  and  Secret  Canons,  Eureka 
District,  Nevada. 


FOSSILS  OF  THE  CAMBRIAN. 


57 


Ptychoparia  granulosus  H.  &  W. 

CrepicepJialus  (Loganellus)  granulosus  Hall  &  Wbitfield,  1877. 
Par.,  vol.  iv,  p.  214,  pi.  ii,  figs.  2,  3. 


Geol.  Expl.  Fortieth 


Types  from  the  Eureka  District.  The  species  occurs  at  the  summit  of 
the  Secret  Canon  shale,  across  the  canon  from  the  dump  of  the  Richmond 
shaft,  Ruby  Hill,  and  in  the  lower  part  of  the  Pogonip  Group,  southeast 
of  the  Jackson  mine,  Eureka  District,  Nevada. 

Ptychoparia  Hague!  H.  &  \V. 

Crepicephalus  (Loganellus)  Haguei  Hall  &  Whitfield,  1877.    Geol.  Expl.  Fortieth  Par., 
vol.  iv,  p.  210,  pi.  ii,  figs.  14, 15. 

Types  from  Pogonip  Mountain,  White  Pine  District,  Nevada. 

In  the  Eureka  District  this  species  has  a  range  nearly  equal  to  that  of 
P.  Gallatinensis,  but,  as  yet  known,  it  does  not  extend  down  below  the  sum- 
mit of  the  Secret  Canon  shale.  At  that  horizon  it  occurs  on  the  eastern 
side  of  Secret  Canon  and  the  opposite  side  of  the  canon  from  the  dump  of 
the  Richmond  shaft,  Ruby  Hill,  and  at  the  summit  of  the  Hamburg  shale 
east  of  the  Hamburg  mine,  and  also  in  the  lower  part  of  the  Pogonip 
Group  at  the  same  locality. 


Ptychoparia  nitidus  H.  &  W. 

Crepicephalus  (Loganellus)  nitidus  Hall  &  Whitfield,  1877.     Geol.  Expl.  Fortieth  Par., 

vol.  iv,  p.  212,  pi.  ii,  figs.  8-10. 
Crepicephalus  (Loganellus}  simulator  Hall  &  Whitfield,  1877.     Geol.  Expl.  Fortieth 

Par.,  vol.  iv,  p.  218,  pi.  ii,  figs.  16-18. 

When  studying  a  large  series  of  specimens  of  Ptychoparia  nitidus  it  was 
observed  that  the  head  and  pygidium  varied  in  size,  and  that  there  were  no 
differences  between  the  larger  sized  specimens  of  the  head  and  the  type  of 
Crepicephalus  (Z/)  simulator. 

The  types  of  the  two  species  described  by  Messrs.  Hall  and  Whitfield 
were  collected  in  the  Eureka  District  by  the  geologists  of  the  Fortieth  Par- 
allel Exploring  Expedition,  and  the  species  is  quite  abundant  in  strata  near 
the  summit  of  the  Cambrian  series. 


58  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

Formation  and  localities. — Hamburg  shale,  in  the  Widewest  Ravine 
north  of  Adams  Hill,  and  also  from  the  same  horizon  a  short  distance  south 
of  the  Hamburg  mine  on  the  east  side  of  the  same  canon,  Eureka  District, 
Nevada;  also  at  about  the  same  horizon  on  Pogonip  Ridge,  White  Pine 
District,  Nevada. 


Ptychoparia  unisulcatus  H.  &  W. 

Crepicephalus  (Loganellus)  unisulcatvs  Hall  &  Wliitfield,  1877.     Geol.  Expl.  Fortieth 
Par.,  vol.  iv,  p.  216,  pi.  ii,  figs.  22,  23. 

The  types  of  this  species  are  cited  by  its  authors  as  coming  from  the 
limestone  of  the  Potsdam  Group  at  Eureka,  Nevada.  It  is  found  associated 
with  P.  Haguei,  in  the  upper  beds  of  the  Secret  Canon  shale,  opposite  the 
dump  of  the  Richmond  mine  shaft,  Ruby  Hill,  on  the  northeast  side  of  the 
canon,  and  in  the  lower  portion  of  the  Pogonip  Group,  northeast  of  Adams 
Hill.  It  also  occurs  in  the  lower  portion  of  the  Pogonip  Group,  on  Pogonip 
Ridge,  White  Pine  District,  Nevada. 


Subgenus  PTEROCEPHALUS  Eoemer. 

Ptychoparia  (Pterocephalus)  occidens,  n.  sp. 
Plate  ix,  iig.  21. 

Glabella  and  fixed  cheeks,  when  united,  irregularly  elongate-quad- 
rangular in  outline,  exclusive  of  the  postero-lateral  limbs;  widest  across 
the  frontal  lobe,  and  curving  in  towards  the  eyelobes;  greatest  width  five- 
sixths  of  the  length.  Glabella  broadly  conical,  rounded  in  front,  and  mod- 
erately convex;  marked  by  a  pair  of  short  posterior  furrows. 

Occipital  ring  narrow,  rounded,  separated  from  the  base  of  the  gla- 
bella  by  a  narrow,  distinct  occipital  furrow;  fixed  cheeks  rather  narrow; 
palpebral  lobes  small,  and  situated  opposite  the  central  portion  of  the  gla- 
bella;  frontal  limb  expanded,  its  length  equaling  more  than  one-third  the 
entire  length  of  the  head;  concave  from  the  front  to  the  back,  and  appar- 
ently without  a  raised  anterior  rim;  postero-lateral  limbs  extended,  the 
suture  line  cutting  the  posterior  margin  some  distance  beyond  the  line  of 


.  FOSSILS  OF  THE  CAMBRIAN. 

the  eyelobes;  marked  near  the  posterior  margin  by  the  extension  of  the 
occipital  groove.  Facial  suture  extends  outward,  with  a  slight  curvature 
in  front  of  the  eyelobe,  and  then  recurves,  rounding  the  lateral  extension 
of  the  frontal  limb;  behind  the  eye  it  extends  backward  and  outward  at  an 
-angle  of  about  45°  for  a  short  distance,  and  then  continues  at  an  angle  of 
25°  to  the  posterior  margin  of  the  head. 

Dimensions. — Length  of  head,  6mra;  breadth  of  frontal  lobe,  2J>5mm; 
length  of  glabella,  including  occipital  ring,  nearly  3.75mm. 

This  distinct  form  appears  to  belong  to  that  division  of  the  Concepha- 
lidae  represented  by  Roemer's  genus  Pterocephalus,  judging  by  its  wide 
frontal  limb  and  the  course  of  the  facial  sutures. 

Formation  and  locality. — Upper  beds  of  the  Cambrian.  On  the  east  side 
of  the  canon  east  of  the  Hamburg  Ridge,  Eureka  District,  Nevada. 


Ptychoparia  (Pterocephalus)  laticeps  H.  &  W. 

Concephalites  (Pterocephalus}  laticeps  Hall  &  Whitfield,  1877. 
Par.,  vol.  iv,  p.  221,  pi.  ii,  figs.  4-7. 


Geol.   Expl.  Fortieth 


This  species  is  given  by  its  authors  as  occurring  in  the  lowest  lime- 
stones on  the  west  side  of  Pogonip  Mountain,  White  Pine  District,  Nevada, 
In  the  Eureka  District  it  is  found  in  the  upper  beds  of  the  Secret  Canon 
shale,  opposite  the  dump  of  the  Richmond  mine  shaft,  Ruby  Hill,  northeast 
side  of  the  canon,  and  in  the  Hamburg  belt  of  shale  east  of  the  Hamburg 
mine,  Eureka  District,  Nevada. 


Genus  ANOMOCARE  Angelin. 

Anomocare  ?  parvum,  n.  ep. 
Plate  ix,  fig.  17. 

Glabella  and  fixed  cheeks  united,  subquadrangular  in  form,  moderately 
convex.  Glabella  tapering  gradually  from  the  base  to  the  front,  where  it 
is  rounded  truncate;  the  surface  is  depressed  convex  and  marked  by  four 
pairs  of  glabellar  furrows,  which  are  short,  slightly  impressed,  and  divide 
the  glabella  into  three  subequal  lobes,  with  a  somewhat  longer  anterior 


60  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

lobe;  occipital  ring  strong,  swollen  towards  the  center,  and  bearing  a  short 
spine;  occipital  furrow  well  defined;  dorsal  furrows  blended  with  the  de- 
pressed interior  slope  of  the  fixed  cheeks  and  frontal  lobe;  this  causes  the 
glabella  to  stand  out  prominently,  although  but  little  elevated  above  the 
general  surface  of  the  head;  fixed  cheeks  rather  broad,  with  a  rounded, 
ridge-like  elevation  near  the  eyelobes,  and  sloping  inward  to  form  a  de- 
pressed space  before  reaching  the  glabella;  eyelobes  large,  with  an  ocular 
ridge  running  towards  the  anterior  lobe  of  the  glabella;  frontal  lobe  short 
and. convex,  merging  into  the  fixed  cheeks  laterally,  and  in  front  into  the 
strong  furrow  within  the  broad,  marginal  border;  the  border  is  convex  and 
swollen  at  the  center  into  a  small  protuberance;  postero-lateral  limbs  nar- 
row and  rather  depressed. 

Surface  finely  granulose. 

The  identification  of  the  genus  Anomocare  is  made  with  the  illustra- 
tions given  by  Angelin,  and,  until  we  know  more  of  the  structure  of  the 
species  under  consideration,  it  is  difficult  to  give  any  other  generic  refer- 
ence. No  pygidise  or  remains  of  the  thoracic  segments  were  found  in  the 
same  association. 

Formation  and  locality. — Cambrian.  In  a  limestone  beneath  the  arena- 
ceous shales  carrying  the  species  of  Olenellus,  given  on  a  previous  page, 
and  associated  with  0.  Gilberti  and  0.  Howelli.  West  slope  of  Prospect 
Mountain,  Eureka  District,  Nevada. 

Genus  PTYCHASPIS  Hall. 

Ptychaspis  minuta  Whitfieltl  (T). 
Plate  x,  tig.  23. 

Ptychaspis  minuta  Whitfield,  1878.    Ann.  Rep.  Wisconsin  Geol.  Surv.,  p.  55.    Ibid., 
Geol.  Wisconsin,  vol.  iv,  p.  186,  pi.  i,  figs.  25,  26,  1883. 

This  is  a  very  minute  form,  the  head  measuring  only  about  3nn"  in 
length  A  comparison  of  the  glabella  and  fixed  cheeks,  the  only  parts  thus 
far  discovered,  with  the  description  of  the  original  type  specimens  from  the 
Potsdam  sandstone  of  Wisconsin,  shows  such  close  resemblances  between 
the  two  that  with  our  present  knowledge  it  appears  impossible  to  consider 


1  OSSILS  OF  THE  CAMBRIAN. 


61 


them  as  specifically  distinct.  The  frontal  limb  scarcely  projects  beyond  the 
front  line  of  the  glabella,  as  it  slopes  abruptly  downward,  although  it  is 
represented  as  projecting  out  some  distance  in  the  specimen  illustrated  owing 
to  a  narrow  seam  of  calcite  crossing  it  and  throwing  it  forward. 

Formation  and  locality. — Cambrian.     Prospect  Mountain  Group,  eastern 
base  of  Lookout  Mountain,  Sierra  Valley,  Eureka  District,  Nevada. 

Genus  CHARIOCEPHALUS  Hall. 

Chariocephalus  (?)  tumifroiis  H.  &  W. 


Geol.  Expl.  Fortieth  Par.,  vol.  iv, 


Plate  x,  fig.  16. 

Chariocephalus  tumifrons  Hall  &  Whitfield,  1877. 
p.  224,  pi.  ii,  figs.  38,  39. 

The  types  of  this  species  came  from  the  lower  limestones  of  Pogonip 
Mountain,  in  the  White  Pine  District,  Nevada. 

The  specimen  illustrated  as  the  type  of  the  species  is  the  extreme  form 
attained  by  the  adult.  Traced  in  a  series  of  individuals,  towards  the  younger 
form,  the  anterior  lobe  of  the  glabella  is  seen  to  lose  its  tumid,  projecting 
character,  and  to  curve  down  to  the  frontal  margin  and  not  overhang  it,  as 
in  the  older  individuals.  One  of  the  intermediate  phases  of  growth  is  shown 
by  fig.  16,  plate  x. 

Formation  and  locality. — Cambrian.  In  the  upper  beds  of  the  Secret 
Caflon  shale  on  the  north  side  of  the  canon,  opposite  the  dump  of  the  shaft 
of  the  Richmond  mine  on  Ruby  Hill,  Eureka  District,  Nevada. 

Genus  AGEAULOS  Cord  a. 

Agraulos  ?  globosus,  n.  sp. 

Plate  ix,  fig.  23. 

Glabella  and  fixed  cheeks,  exclusive  of  the  postero-lateral  limbs,  sub- 
quadrate,  strongly  convex.  Glabella  with  the  sides  and  front  rounded, 
convex,  and  with  the  surface  apparently  smooth;  dorsal  furrows  well 
defined;  occipital  ring  not  perceptibly  separated  from  the  glabella;  fixed 
cheeks  of  medium  width;  palpebral  lobes  small,  the  cheeks  sloping  down 
to  them;  frontal  limb  about  one-third  as  long  as  the  glabella,  convex,  with- 
out an  apparent  marginal  rim,  and  with  a  slight  furrow  at  the  union  with 


62  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

the  fixed  cheeks;  postero-lateral  limbs  strong,  extended  laterally  and  with 
a  distinct  marginal  furrow,  which  is  usually  the  continuation  of  the  occipital 
furrow.  Facial  suture  directed  gently  forward  from  the  eyelobe  towards 
the  front,  recurving  to  the  frontal  margin  of  the  head  so  as  to  round  the 
lateral  angles  of  the  frontal  limb;  behind  the  eye  it  passes  to  the  posterior 
margin  at  an  angle  of  20°— 25°  with  the  latter,  outlining  a  triangular-shaped 
lateral  lirnb. 

This  peculiar  little  species  (the  head  is  but  3mm  in  length)  appears  to 
unite  some  embryonic  features  with  those  of  the  adult  individual.  It  is 
doubtfully  referred  to  Agraulos.  The  discovery  of  allied  species  or  more 
specimens  of  this  one  may  enable  the  observer  to  determine  more  fully  its 
true  generic  relations. 

Formation  and  locality. — Cambrian.  In  a  small  outcrop  of  limestone  on, 
the  west  side  of  the  Eureka  District,  Nevada. 

Genus  ARETHUSINA  Barrande. 

Arethusina  Americana,  n.  sp. 
Plate  ix,  fig.  y~. 

Glabella  and  fixed  cheeks  united,  a  little  wider  than  long,  the  front 
broadly  rounded,  and  the  sides  a  little  contracted  midway.  Glabella  promi- 
nent, conical,  convex,  rounded  in  front,  and  marked  by  two  pairs  of  short 
furrows  extending  obliquely  inward  less  than  one-fourth  the  distance 
across;  occipital  ring  narrow,  defined  by  a  shallow  occipital  furrow;  fixed 
cheeks  broad,  sloping  away  from  the  well-defined  dorsal  furrows  to  the 
minute  palpebral  lobes;  well-marked  ocular  ridges  cross  from  opposite  the 
anterior  portion  of  the  glabella  to  the  eyelobes;  all  in  front  of  these  is 
occupied  by  the  broad,  expanded  frontal  limb;  it  is  slightly  convex  to  the 
anterior  narrow  marginal  rim;  postero-lateral  limbs  but  little  extended  lat- 
erally and  with  a  marginal  groove  within  the  posterior  border.  Facial 
suture  extends  a  little  outward  in  a  gentle  curve  to  the  frontal  margin  from 
the  eyelobe,  recurving  just  before  reaching  the  margin;  behind  the  eye- 
lobe  it  is  directed  obliquely  backward,  outlining  a  triangular  lateral  limb 
and  cutting  the  posterior  margin  at  a  distance  from  the  dorsal  furrow  equal 
to  the  width  of  the  glabella  at  its  base. 


FOSSILS  OF  THE  CAMBRIAN.  03 

Surface  of  the  glabella  minutely  granulose ;  the  frontal  limb  has  a 
peculiar  ornamentation  formed  by  irregular  inosculating  lines  that  in  their 
general  direction  radiate  towards  the  anterior  rim. 

With  the  portions  of  this  species  we  have  before  us,  it  appears  to  be 
related  to  Arethusina  more  closely  than  any  other  described  genus.  The 
posterior  glabellar  furrows  are  less  oblique  than  in  the  Bohemian  species, 
but  otherwise  there  is  a  strong  generic  resemblance  between  them. 

Formation  and  localities. — Upper  beds  of  the  Cambrian.  On  the  ridge 
north  of  the  Dunderberg  mine,  at  about  the  same  horizon  on  the  north 
side  of  the  canon  north  of  Adams  Hill,  and  also  in  the  Pogonip  Group, 
on  the  second  ridge  southeast  of  the  Jackson  mine,  Eureka  District,  Nevada, 

Genus  OGYGIA  Brongniart. 

Ogygia  ?  spinosa,  n.  sp. 

Plate  ix,  fig.  22. 

Glabella  elongate,  not  quite  twice  as  long  as  wide ;  sides  parallel 
nearly  to  the  front,  which  is  slightly  expanded  and  broadly  rounded  ante- 
riorly; moderately  convex  and  subangular  along  the  median  line;  marked 
by  three  pairs  of  oblique  furrows  that  extend  one-third  the  distance  across; 
occipital  ring  strong,  not  very  convex,  and  with  a  rather  strong  central 
spine  projecting  backward  and  upward;  occipital  furrow  shallow,  well 
defined;  fixed  cheeks  narrow;  palpebral  lobes  large,  rising  slightly  from 
the  dorsal  furrows  to  the  depressed  furrow  just  within  and  parallel  to  their 
margins;  frontal  limb  convex,  of  medium  width  and  length,  and  bordered 
by  a  flattened  rim.  The  presence  of  the  strong  occipital  spine  is  one  of 
the  most  distinct  characters  of  this  species. 

Formation  and  locality. — Cambrian.  Prospect  Mountain  Group;  at  the 
base  of  the  Secret  Canon  shale  in  Secret  Canon,  Eureka  District,  Nevada. 


Ogygia  ?  problematica,  n.  sp. 
Plate  x,  tigs.  2a-6,  and  4. 

Glabella  elongate,  clavate,  expanding  regularly  from  the  base  to  a 
width   one-third  greater  in   front;  moderately  convex  behind,   becoming 


64  PALEONTOLOGY  OF  THE  EUREKA  DISTEICT. 

almost  tumid  on  the  frontal  lobe,  and  in  compressed  examples  slightly 
projecting  over  the  anterior  margin;  marked  by  three  pairs  of  oblique, 
slightly  impressed  furrows;  these  are  united  across  the  center  by  short 
transverse  depressions;  occipital  furrow  shallow;  occipital  ring  strong, 
flattened;  fixed  cheeks  of  medium  width,  separated  from  the  glabella  by 
distinct  but  lightly  impressed  dorsal  furrows,  and  sloping  outward  to  the 
medium-sized  eyelobes;  postero-lateral  limbs  strong  and  well  extended 
laterally;  frontal  limb  as  a  narrow  margin  close  to  the  front  of  the  glabella. 

The  facial  sutures  have  the  general  course  of  those  in  the  genera 
Ogygia  and  Asaphus. 

The  above  description  is  drawn  from  a  well-preserved  adult  specimen 
of  the  head,  that,  excepting  the  free  cheeks,  is  23mm  in  length.  In  a  young 
example  of  the  same  parts,  7mm  in  length,  the  glabella  is  less  convex, 
subangular  in  front,  sloping  to  the  margin,  and  the  glabellar  furrows  are 
obsolete;  in  other  respects  it  strongly  resembles  the  adult. 

With  these  parts  before  us  we  would  refer  the  species  to  Ogygia;  but 
in  every  instance  where  they  have  been  found  there  are  pygidise,  tho- 
racic segments  and  fragments  associated  with  them  that  indicate  an  entirely 
different  genus.  An  illustration  is  given  of  the  pygidium  on  plate  x,  fig. 
2 a,  and  of  the  segment,  fig.  2b.  They  occur  in  association  along  an  out- 
crop of  several  miles,  and  no  other  species  of  a  similar  size  is  known  to 
exist  at  the  same  horizon.  No  genus  known  to  us  combines  the  characters 
presented  by  the  head  and  pygidium,  and,  although  they  have  not  been 
seen  united  to  the  thorax,  the  evidence  is  in  favor  of  their  belonging  to 
the  same  species. 

A  provisional  reference  is  made  to  Ogygia,  the  genus  to  which  the 
head  appears  to  belong,  the  pygidium  and  thoracic  segments  having  more 
the  character  of  those  referred  to  Dicellocephalus. 

Formation  and  localities. — Cambrian.  Prospect  Mountain  Group,  upper 
beds  of  the  Secret  Canon  shale,  on  the  east  side  of  Secret  and  New  York 
Canons,  and  on  the  south  slope  of  Adams  Hill,  Eureka  District,  Nevada. 


FOSSILS  OF1  THE  LOWER  SILURIAN. 

POGONIP  GROUP. 

RHIZOPODA. 
,  Genus  EECEPTACULITES  Defrance. 

Receptaculites  mammillaria  Newberry. 

Plate  xi,  fig.  11. 
Receptaculites  mammillaris  Newberry,  1880.    Name  proposed  in  manuscript. 

There  is  quite  a  range  in  the  forms  taken  by  this  species,  the  most 
prevalent  of  which  is  an  inverted  cone  with  a  deep  depression  on  the  upper 
surface,  the  height  being  to  the  diameter  of  the  summit  as  four  to  five. 
In  the  more  expanded  examples,  with  the  height  and  diameter  as  one  to 
two,  the  base  is  small,  and  when  the  specimens  are  reversed,  form  a  nipple- 
like  projection  on  the  summit  of  the  broadly  rounded  surface.  The  walls 
have  a  thickness  of  about  18mm,  in  examples  from  40mm  to  f>0mm  in  diam- 
eter. 

The  outer  surface  or  ectorhin  is  formed  of  rhomboidal  plates  arranged 
in  radiatingly  curved  lines  crossing  each  other  obliquely;  the  plates  near 
the  base  have  a  greater  diagonal  axis  of  lmm,  which  gradually  increases  to 
2.5mm  in  the  plates  towards  the  summit;  the  only  surface  character  preserved 
is  a  slight  depression  in  the  center  of  each  plate.  The  cylindrical  tubes 
uniting  the  ectorhin  and  endorhin  have  the  characteristic  construction  of  such 
tubes  in  Receptaculites  near  the  base,  but  have  not  the  connecting  stolons 
or  tubes  between  the  constrictions  and  the  ectorhin.  Their  absence  may 
be  owing  to  the  imperfect  condition  of  the  specimens  examined.  Along  the 
upper  portion  of  the  tubes  there  is  a  series  of  annulations,  ten  in  a  distance 
of  6mm,  that  appear  to  be  made  up  of  little  projections  or  stolons  uniting 
the  tubes  on  the  upper  annulations. 

5  c  D  w  65 


66  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

In  the  mode  of  growth  and  general  form  this  species  is  related  to  E. 
Neptuni,  but  differs  in  the  details  of  structure. 

Several  years  since  Dr.  J.  S.  Newberry  obtained  examples  of  the 
species  from  the  White  Pine  Mining  District,  and  also  from  Pioche,  Nevada, 
proposing  the  specific  name  E.  mammilaris,  in  his  notes,  on  account  of 
the  appearance  of  the  more  expanded  forms  with  the  nipple-like  base.  An 
illustration  is  given  of  the  most  abundant  form  in  the  Eureka  District. 
The  complete  illustration  of  this  and  its  associated  species  of  the  genus  is 
deferred  until  sections  can  be  prepared  to  exhibit  the  details  of  structure. 

Formation  and  localities. — Upper  portion  of  the  Pogonip  Group  at  Lone 
Mountain,  18  miles  northwest  of  Eureka;  White  Mountain,  Fish  Creek 
Mountains,  and  Goodwin  Canon  in  the  Eureka  District;  and  also  at  Pioche 
and  Treasure  City,  White  Pine  Mining  District,  Nevada. 

Receptaculites  elongatus,  n.  sp. 

The  general  form  of  this  species  is  cylindro-conical,  with  the  central 
depression  extending  deep  down  into  the  body,  the  thickness  of  the  sides 
near  the  base  and  at  the  summit  being  nearly  the  same.  The  outline  of 
the  central  depression  is  circular,  and  there  is  no  evidence  of  the  growth 
of  the  sides  over  it  as  in  some  species  of  the  genus  from  Canada  and 
Wisconsin,  e.  g.,  E.  Jonesi,  E.  fungosum,  etc.  The  ectorhin  is  formed  of 
small  rhomboidal  plates,  arranged  as  in  other  forms  of  the  genus ;  the  largest 
plates  have  a  greater  diagonal  diameter  of  about  lmm,  and  a  lesser  one  of 
about  five-sixths  of  lmm.  The  cylindrical  tubes  uniting  the  ectorhin  and 
endorhin  are  small,  constricted  at  the  base,  and  apparently  smooth  up  to 
their  union  with  the  plates  of  the  endorhin.  The  sides  of  a  specimen  45mm 
high,  and  with  a  transverse  diameter  of  20mm,  have  a  thickness  of  lKm  above 
and  of  5mm  near  the  base 

This  species  is  distinguished  from  any  known  to  me  by  its  cylindro- 
conical  form,  deep  central  cavity,  and  small  cells  or  tubes.  It  approaches 
E.  insularis  Billings,  of  the  Middle  Silurian  of  the  island  of  Anticosti  (Cat. 
Sil.  Foss.  Anticosti,  p.  29,  1866),  but  differs  in  having  the  deep  central  de- 
pression and  a  less  rapidly  tapering  form;  these  features,  united  with  the  fact 


FOSSILS  OF  THE  LOWER  SILURIAN. 


67 


of  the  great  vertical  difference  in  the  geologic  horizon  at  which  the  two 
forms  occur,  render  the  probability  of  a  specific  identity  very  doubtful. 

Formation  and  localities. — Upper  portion  of  the  Pogonip  Group,  White 
Mountain  and  Goodwin  Canon,  Eureka  District,  Nevada.  Also  in  the  col- 
lection of  the  School  of  Mines,  Columbia  College,  New  York,  collected  by 
Dr.  J.  S.  Newberry  in  the  Pahranagat  Range,  Nevada. 

Receptaculites  ellipticus,  n.  sp. 
Plate  xi,  fig.  12. 

This  is  an  elongate,  flattened,  curved  form,  with  a  strongly  elliptical 
transverse  section,  the  curvature  being  with  the  major  diameter  of  the 
section.  The  central  depression  is  deep,  but  not  as  large  proportionally  as 
in  R.  elongatus.  The  plates  of  the  ectorhin  are  of  medium  size,  1.75mm  by 
1.25mm,  and  arranged  as  in  the  preceding  species.  The  cylindrical  tubes 
uniting  the  ectorhin  and  endorhin  are  strong  and  appear  to  be  round  and 
smooth,  except  where  marked  by  the  constriction  and  connecting  basal 
stolons.  The  plates  of  the  endorhin  are  concealed  by  the  adhering  matrix 
in  all  the  examples  in  the  collection. 

The  illustration  shows  the  curvature  and  general  form  of  a  well-marked 
example  of  the  species.  It  is  specifically  distinct  from  any  described  form 
that  we  know  of,  although  allied  to  Receptaculites  infundibulus  Hall  (Rep, 
Geol.  Surv.  Wisconsin,  8vo,  pam.,  p.  16,  1861)  —  Ischadites  tessellatus  Win- 
chell  and  Marcy,  of  the  Niagara  Group  of  Illinois  (Mem.  Bos.  Soc.  Nat.  Hist., 
vol.  i,  p.  85,  pi.  ii,  fig.  3,  1865),  from  which  it  differs  in  the  size  of  the 
ectorhinal  plates  and  other  details  of  structure. 

Formation  and  localities. — Upper  portion  of  the  Pogonip  Group,  White 
Mountain,  Goodwin  Canon,  and  Fish  Creek  Mountains,  Eureka  District, 
Nevada. 

BRACHIOPODA. 

Genus  OBOLELLA  Billings. 

Obolella  ?  ambigua,  u.  sp. 
Plate  i,  fig.  2  a,  b,  c. 

Shell  of  medium  size  for  the  genus  as  now  known,  ovate,  moderately 
convex;  surface  lamellose;  shell  calcareous.  Ventral  valve  ovate,  broadly 


68  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

rounded  in  front,  widest  one-third  the  length  from  the  front,  thence  round- 
ing and  narrowing  gently  to  the  beak,  which  is  rather  broadly  rounded ; 
area  unknown.  The  dorsal  valve  is  transversely  ovate  to  subcircular,  beak 
emarginate. 

The  interior  of  the  ventral  valve  is  unknown  ;  that  of  the  dorsal  valve 
shows  a  central  median  depression  divided  centrally  by  a  narrow  raised  line; 
towards  the  beak  the  depression  is  broader,  narrowing  midway,  and  dividing 
before  reaching  the  center  of  the  shell;  a  large  muscular  scar  occurs  each  side 
of  the  central  depression,  and  also  a  depressed  line  a  little  beyond  them  that 
runs  out  obliquely  from  the  beak.  There  appears  to  be  a  muscular  scar  on 
each  side  of  the  center  of  the  median  depression  just  at  its  bifurcation.  No 
other  scars  could  be  detected. 

In  external  form  and  character  this  species  is  allied  to  Obolella  gemma, 
and  0.  chromatica  of  Billings.  The  arrangement  of  the  muscular  scars  in  the 
smaller  valve  is  peculiar  and  the  shell  is  also  thinner  than  in  the  above 
species. 

The  generic  reference  is  made  with  a  query  as  in  comparing  it  with  the 
dorsal  valve  of  Obohlla  sagittalis  Salter,  as  illustrated  by  Davidson,  we  find 
a  marked  difference  and  would  scarcely  refer  the  two  to  the  same  genus. 
In  a  comparison  with  American  species  the  reference  would  be  to  Obolella, 
as  the  interior  of  the  dorsal  valve  has  not  been  given  in  the  typical  species, 
and  that  of  Obolella  polita  has  little  if  any  more  than  a  strong  specific  varia- 
tion from  that  of  0.  f  anibigua. 

Mr.  Davidson,  in  speaking  of  the  species  arranged  under  Obolella,  says 
that  the  diagnosis  of  the  genus  will  require  modification  before  it  can  com- 
prise 0.  chromatica  (the  type)  0.  f  polita,  0.  f  Saltcri,  0.  desiderata,  etc.  From 
our  limited  study  and  comparisons  it  does  not  appear  that  all  these  can  be 
united  under  one  genus — 0.  polita  and  0.  anibigua  presenting  one  type,  0. 
gemma  and  0.  desquamata  another,  and  0.  sagittalis  Salter,  still  another  among 
the  species  now  referred  to  the  genus 

Formation  and  locality. — Pogonip  Group.  Base  of  Silurian.  East  slope 
of  ridge  east  of  the  Hamburg  mine,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


69 


Genus  SCHIZAMBON,  n.  g. 

Shell  ovate  or  oblong1  oval,  inequi valve;  valves  inarticulate;  larger  or 
ventral  valve  most  convex,  with  a  short  obtuse  beak  at  the  cardinal  margin. 
Foramen  oblong  and  opening  on  the  summit  of  the  valve,  no  area  nor  delti- 
dium;  cardinal  edge  thin;  smaller  or  dorsal  valve  nearly  as  convex  as  the 
larger,  slightly  flattened  along  the  median  line. 

Structure  calcareo-corneous,  consisting  of  a  nacreous  outer  layer  with 
a  closely  attached  inner  calcareous  layer.  Both  layers  are  thought  to  be 
punctured  by  scattered  tabulae.  Surface  smooth  or  with  distinct  lines  of 
growth  and  scattered  spines  apparently  on  the  outer  edges  of  the  laminae  or 
lines  of  growth. 

The  interior  of  the  larger  valve  shows  the  oblong  foramen  in  a  slight 
elongate  depression  and  a  pair  of  muscular  scars  just  in  front  of  it  on  each 
side  of  a  slight  longitudinal  depression;  from  near  the  beak  on  each  side  of 
the  foramen,  a  shallow  sharply  defined  depression  extends  obliquely  out- 
ward. No  other  markings  were  observed.  In  the  interior  of  the  dorsal 
valve  a  pair  of  anterior  central  muscular  scars  terminate  their  path  of  ad- 
vance from  the  beak,  a  slight  rounded  ridge  rising  on  the  central  line;  pos 
terior  to  these  a  larger  pair  occur,  and  still  beyond  and  more  posterior  a 
third  pair,  a  narrow  rounded  ridge  extending  obliquely  down  from  the  beak 
on  each  side  between  the  central  and  lateral  scars. 

The  above  description  is  based  on  a  large  number  of  specimens.  Nu- 
merous interiors  of  the  valves  occur  owing  to  the  rough  outer  surface  cling- 
ing to  the  fine  arenaceous  limestone  matrix.  In  the  interiors  little  pits 
occur  scattered  irregularly  over  the  surface,  and  on  the  outside  similar  pits 
are  seen.  It  is  difficult  to  determine  whether  these  communicate  with  each 
other.  Judging  from  their  appearance  and  also  from  a  cross-section  of  the 
shell  that  shows  minute  tubulse  nearly  through  the  shell,  we  are  inclined  to 
consider  the  shell  as  punctate.  The  little,  short  spines  of  the  outer  surface 
have  the  form  of  those  on  Siphonotreta ;  whether  they  are  hollow  or  not  has 
not  been  determined. 

The  most  nearly  related  genera  are  Acrothele  and  Acrotreta.  It  is 
unlike  Acrothele  in  the  structure  of  its  shell,  in  the  position  of  the  opening 


70  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

on  its  ventral  valve  with  relation  to  the  apex  of  the  valve  and  in  the  absence 
of  any  indication  of  a  false  area.  The  general  facies  of  the  shell  also  suggests 
another  generic  group.  Its  affinity  with  Acrotreta  consists  in  the  presence 
of  the  three  pairs  of  muscular  scars  in  the  smaller  valves  and  in  the  perforate 
larger  valve.  The  surface  structure  and  general  form  closely  ally  it  to 
Siphonotreta,  and  I  would  refer  Siphonotreta  fissa  Kutorga,  to  this  genus, 
as  in  all  external  characters  it  is  almost  specifically  related  to  Schizambon 
typicalis. 

Schizambon  typicalis,  n.  sp. 
Plate  i,  figs.  3a-d. 

Shell  small,  longitudinally  ovate;  length  and  breadth  nearly  the  same; 
front  and  .side  margins  broadly  rounded;  posterior  margin  of  the  ventral 
valve  slightly  acuminate,  of  the  dorsal  valve  broadly  rounded,  except  a 
very  slight  projection  at  the  center.  The  ventral  valve  has  a  small,  oblong 
foramen  near  the  apex,  with  a  gradually  narrowing  depression  extending 
to  the  posterior  extremity.  Both  valves  are  slightly  convex,  the  ventral 
one  the  more  so.  Surface  marked  by  lamellose  concentric  raised  lines, 
bordered  with  fine  spines  on  the  outer  portions  of  the  shell.  Towards  the 
beak  numerous  fine  concentric  striae  appear. 

The  shells  consist  of  an  outer  nacreous  layer,  with  an  exceedingly  thin 
inner  calcareous  layer  closely  attached  to  it.  As  has  been  mentioned  under 
the  generic  description,  the  shell  appears  to  be  punctate.  In  many  instances 
scarcely  a  pit  is  seen  on  the  inside  of  the  shell,  while  in  others  they  are 
scattered  quite  thickly  over  the  surface.  The  largest  specimens  obtained 
measured  5mm  in  length  by  4.5mm  in  breadth. 

In  the  ventral  valve,  fig.  3,  the  margin  of  the  siphonal  opening  is 
slightly  elevated  and  extends  quite  to  the  beak,  leaving  a  triangular,  elon- 
gate, narrow  depression  behind  the  opening.  Starting  near  the  beak  and 
running  obliquely  outward  a  slightly-depressed,  narrow,  smooth  line  shows 
the  advance  of  a  muscular  scar;  between  this  and  the  siphonal  opening  a 
smooth  space  intervenes,  in  the  front  of  which  a  pair  of  muscular  scars  can 
be  detected.  A  slight  depression  extends  forward  in  advance  of  the  siphonal 
opening. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


71 


The  dorsal  valve,  fig.  36,  shows  a  narrow  median  ridge  with  a  pair  of 
minute,  elongate,  oval  scars  at  its  front  termination  (a,  a) ;  posterior  to  these 
and  between  the  central  ridge  and  a  low  ridge  extending  from  the  beak 
obliquely  outward  and  forward  a  larger,  reniform  scar  occurs  on  each  side 
(p,  a) ;  outside  of  the  narrow  lateral  ridges  and  on  the  posterior  lateral  por- 
tion of  the  shell  another  minute  scar  is  seen  on  each  side  (a,  d).  None  of 
the  specimens  show  a  scar  beneath  the  beak. 

A  comparison  with  the  figures  of  Siphonotreta  fissa  Kutorga6  shows  a 
strong  generic  relation,  judging  from  the  external  characters;  specifically 
they  have  several  points  in  common. 

The  species  occurs  in  the  passage  beds  at  the  base  of  the  Pogonip 
Group  in  the  same  band  of  layers  carrying  Acrotreta  gemma,  Lingulepis, 
Discina,  Orthis,  Camarella  calcifera,  Ptychoparia  Oweni,  Dicellocephalus 
finalis,  Illcenurus  Eurekensis,  Amphion,  Barrandia  McCoyi,  etc. 

Formation  and  locality. — Lower  portion  of  Pogonip  Group.  East  slope 
of  ridge  east  of  the  Hamburg  mine  Canon,  Eureka  District,  Nevada. 


Genus  STROPHOMENA  Rafinesque. 

Strophomena  Nemea,  H.  &  W. 

Strophomena  Nemea,  Hall  &  Whitfield,  1877.     Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  233, 
pi.  i,  fig.  15. 

This  species  occurs  in  the  upper  beds  of  the  Pogonip  Group  at  Lone 
Mountain,  18  miles  northwest  of  Eureka,  at  the  same  horizon  on  McCoy's 
Ridge,  and  a  little  lower  down  in  the  strata  on  the  west  slope  of  Secret 
Canon  road  Canon,  Eureka  District,  Nevada. 

The  original  type  of  the  species  is  from  Pogonip  Mountain,  White 
Pine  District,  Nevada. 

6Uber  die  BracMopoden-Familie  der  Siphonotretsese.  Verhandl.  der  Kuss.  Kais.  Mineral.  Gesell- 
schaft,  1848,  p.  250,  pi.  vii,  figs.  5a-c. 


72  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

Genus  ORTHIS  Dalman. 

Orthis  perveta  Courad. 
Plate  xi,  figs.  3,  3«,  b. 

Orthis  perveta  Conrad,  1843.    Proc.  Acad.  Nat.  Sci.  Phila.,  vol.  i,  p.  333. 

Hall,  1852.    Pal.  New  York,  vol.  i,  p.  120,  pi.  xxxii,  figs.  5a-c.    Ibid. 

Geology  of  Wisconsin,  p.  42,  figs.  7«-<Z,  1862. 
Billings,  18G3.    Geol.  Canada,  p.  130,  figs.  57  a-f. 

This  species  is  quite  abundant  in  the  upper  beds  of  the  Pogonip  Group 
at  Lone  Mountain,  and  it  also  ranges  through  nearly  1,000  feet  of  the  lime- 
stone of  White  Mountain,  and  is  found  at  about  the  same  horizon  on  the 
eastern  slope  of  the  ridge  east  of  the  Hamburg  mine,  as  in  the  lower  beds  of 
White  Mountain. 

A  direct  comparison  of  the  Nevada  specimens  with  the  types  of  the 
species  in  the  American  Museum  collections  show  their  specific  identity, 
and  also  that  similar  variations  occur  in  examples  from  the  widely-separated 
localities.  In  Wisconsin  it  is  found  in  the  Trenton  limestone,  and  in  Canada 
Mr.  Billings  identified  it  from  the  Chazy  limestone. 

A  small  but  quite  perfect  specimen  is  illustrated.  Owing  to  the  partial 
exfoliation  of  the  shell,  the  radiating  strife  are  not  as  strong  as  on  the  unin- 
jured surface. 

In  the  expedition  of  1882  this  species  was  found  in  the  upper  part  of 
the  Pogonip  Group,  on  Pogonip  Ridge,  White  Pine  District,  Nevada. 

Orthis  testudiiiaria,  Daliuan. 
Plate  xi,  figs.  10,  10  a. 

Orthis  testudinaria  Dalraau,  1827.    Vet.  Acad.  Hand.,  Stockholm,  p.  115. 

Orthis  testudinaria  Conrad,  1839.     Emmous,  1842 ;  Hall,  1852.     Pal.  N.  Y.,  vol.  i,  p.  117r 

pi.  32,  tigs.  I  a-l.     Whitfield,  Geol.  of  Wisconsin,  vol.  iv,  p.  258,  pi.  xii,  figs. 

5.  7,  1883. 
See  Davidson's  Monograph  British  Silurian  Brachiopoda. 

After  comparing  our  specimens  with  those  from  New  York,  Ohio,  and 
Wisconsin,  we  are  unable  to  discover  any  differences  of  specific  value  be- 
tween them,  although  the  eastern  forms  are  from  the  Trenton  Groups  Tren- 
ton limestone  and  Hudson  River  formations,  and  the  Eureka  specimens 


FOSSILS  OF  THE  LOWER  SILURIAN. 


73 


from  the  horizon  of  the  Chazy  limestone  and  Calciferous  sand-rock  of  the 
New  York  series.  This  identification  and  reference  gives  a  greater  vertical 
and  geographic  range  to  a  species  already  distinguished  for  its  wide  dis- 
tribution. In  England  it  ranges  from  the  Llandeilo  into  the  Lower  Lland- 
overy,  and  it  is  also  known  in  Ireland,  Scotland,  and  Sweden. 

Formation  and  localities. — Pogonip  Group,  summit  of  White  Mountain, 
and  about  1,000  feet  below  that  horizon  on  east  slope  of  ridge  east  of  the 
Hamburg  mine,  Eureka  District,  Nevada,  and  at  the  same  horizon  on  the 
north  end  of  Pogonip  Ridge,  White  Pine  District,  Nevada. 


Orthis  Hamburgensis,  n.  sp. 
Plate  xi,  figs.  f>,  5  a. 

Shell  small,  suborbicular  in  outline,  plano-convex;  hinge  line  a  little 
shorter  than  the  greatest  breadth  of  the  valves.  Dorsal  valve  moderately 
convex,  most  elevated  a  little  behind  the  center,  along  a  slight  ridge  formed 
by  two  or  three  strong,  slightly-raised  striae ;  beak  small,  depressed  about 
half-way  down  to  the  cardinal  margin.  Ventral  valve  depressed,  slightly 
convex,  mesial  depression  well  defined  from  the  beak  to  the  front  margin. 

Surface  of  both  valves  marked  by  from  12  to  1 8  strong  angular  striae, 
which  increase  by  bifurcation  or  intercalation  towards  the  margin. 

This  species  is  represented  by  many  separate  valves,  but  none  show  the 
area  of  either  valve.  It  is  allied  to  0.  testudinaria,  but  differs  essentially  in 
the  surface  ornamentation,  which  is  more  like  that  of  0.  plicatella  in  the  fissi- 
costate  character  of  the  stria?.  A  comparison  with  the  adult  shells  of  0.  pli- 
catella and  0.  fissicosta  shows  that  their  surface  characters  are  strongly  devel- 
oped in  0.  Hamburgensis,  while  in  the  young  shells  of  the  same  species  of 
the  size  of  the  latter  these  features  are  not  present. 

Formation  and  localities. — Central  part  of  Pogonip  Group,  on  the  east 
slope  of  the  ridge  east  of  the  Hamburg  ridge;  on  the  east  slope  of  the 
second  ridge  southeast  of  the  Jackson  mine,  and  also  on  the  second  ridge 
east  of  Secret  Canon,  Eureka  District,  Nevada. 


74  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Orthis  Lonensis,  n.  sp. 
Plate  xi,  figs.  6,  Ca. 

Shell  of  medium  size,  transversely  semi-oval,  width  and  length  as  4  to 
3;  hinge  line  about  equal  to  the  greatest  breadth  of  the  valves. 

Ventral  valve  elevated,  convex;  the  greatest  convexity  a  little  behind 
the  middle  on  each  side  of  a  shallow,  broad  mesial  sinus;  beak  small,  not 
projecting  backward;  area  high  at  the  beak,  sloping  rapidly  to  the  lateral 
margins;  slightly  arched,  and  standing  at  nearly  right  angles  to  the  plane 
of  the  valve;  foramen  a  little  higher  than  broad,  with  its  apex  extending  to 
the  termination  of  the  beak.  Dorsal  valve  unknown. 

Surface  ornamented  by  distinct  radiating  striae  that  increase  by  inter- 
calation, and  curve  gradually  outward  to  the  postero-lateral  margins. 

This  species  belongs  to  that  group  of  Orthis,  of  which  0.  occidentalis  is 
a  type,  and  appears  to  be  specifically  distinct  from  any  described  species. 

Formation  and  locality. — Pogonip  Group,  upper  beds,  Lone  Mountain, 
18  miles  northwest  of  Eureka,  Nevada. 

Orthis  tricenaria,  Coiirad. 
Plate  xi,  figs.  4,  4  a. 

Orthis  tricenaria  Conrad,  1843.    Proc.  Acad.  Nat.  Sci.,  vol.  i,  p.  333. 

Orthis  tricenaria  Hall,  1852.    Pal.  N.  Y.,  vol.  i,  p.  121,  pi.  xxxi,  figs.  8  a,  c.    Ibid.,  Geol. 

Surv.  Wisconsin,  vol.  i,  p.  42,  figs.  8-11,  1862. 
Orthis  tricenaria  Billings,  1863.    Geol.  Canada,  p.  167,  figs.  151  «,  &. 

An  examination  of  a  good  series  of  specimens  of  this  species  shows  that 
it  varies  a  little  in  the  number  and  strength  of  the  surface  striae  in  both  the 
young  and  old  shells,  the  variation  extending  from  the  average  number 
of  28  to  30.  to  16  as  the  minimum  and  35  as  the  maximum;  with  this  in 
view,  the  specimens  from  the  Pogonip  Group  (upper  beds,  at  Lone  Mount- 
ain and  Surprise  Peak)  cannot  well  be  specifically  separated  from  those  of 
Wisconsin  and  New  York.  The  general  form  of  the  shell  is  the  same,  and 
the  number  of  radii  varies  from  16  to  30.  Some  of  the  examples  are  almost 
typical  forms  of  Orthis  costalis,  of  the  Chazy  limestone  of  New  York,  and  a 
comparison  of  specimens  shows  the  two  species  to  be  closely  allied.  It  may 
be  considered  that  the  Nevada  form  is  a  variety  of  0.  tricenaria,  and  worthy 


FOSSILS  OF  THE  LOWER  SILURIAN. 


75 


of  a  distinct  name,  but  until  there  is  more  evidence  than  at  present,  we  pre- 
fer to  recognize  it  as  coming  within  the  limits  of  the  eastern  species. 

Formation  and  locality. — Pogonip  Group  at  Lone  Mountain,  18  miles 
northwest  of  Eureka,  and  on  Surprise  Peak,  Eureka  District,  Nevada.  It 
also  occurs  at  the  same  horizon  on  Pogonip  Ridge,  White  Pine  District, 
Nevada. 

Genus  STREPTORHYNCHUS  King. 

Streptorhyiictms  minor,  u.  sp. 
Plate  xi,  fig.  9. 

Shell  small,  transverse,  semi-oval ;  hinge  line  fully  equaling  the  greatest 
breadth ;  lateral  extremities  nearly  rectangular. 

Ventral  valve  moderately  convex  along  each  side  of  a  rather  broad 
mesial  depression,  extending  from  the  umbo  to  the  front  margin;  postero- 
lateral  regions  flattened  within  the  margin ;  beak  minute  and  scarcely  to  be 
distinguished  from  the  cardinal  margin.  Dorsal  valve  unknown. 

Surface  of  ventral  valve  ornamented  with  rather  fine  radiating  striae 
that  increase  by  intercalation  towards  the  front  margin. 

Length  of  specimen,  6mm;  breadth,   llmm;  convexity,  about  1.25mm. 

This  little  shell  presents  the  characters  of  a  resupinate  Strophomena, 
and  is  therefore  placed  under  the  genus  Streptorhynchus.  It  may  be  com- 
pared with  young  shells  of  Streptorhynchus  sinuatus  Emmons  (Pal.  Ohio,  vol. 
1,  p.  87,  pi.  v,  figs.  5  a-/,  1873),  but  it  appears  to  be  a  distinct  species  from 
any  described. 

Formation  and  locality. — Pogonip  Group,  upper  beds,  at  Lone  Mountain, 
18  miles  northwest  of  Eureka,  Nevada. 

Genus  TRIPLESIA  Hall. 

Triplesia  calcifera  Billings. 

Plate  xi,  figs.  7,  8. 

Camerella  calcifera  Billings,  1861.     Canadian  Nat.  and  Geol.,  vol.  vi,  p.  318,  figs.  3  a-c. 
-Geol.  Canada,  p.  231,  figs.  247  a-c,  1863.    Pal.  Foss.,  vol.  i,  p.  220,  1865. 

There  is  considerable  variation  among  the  specimens  referred  to  this 
species  in  the  collection,  and  two  species  appear  to  be  indicated.  In  one 
the  mesial  depression  is  shallow  with  broadly-rounded  sides,  and  in  the 
other  it  is  deeper  and  more  angular.  In  the  dorsal  valves  the  variation  is 


76  PALEONTOLOGY  OF  THE  EUKEKA  DISTEICT. 

quite  as  great,  but  with  more  gradations  between  the  valves  with  a  scarcely 
perceptible  median  fold  and  those  where  the  fold  is  the  prominent  feature. 

The  figure  of  the  ventral  valve,  fig.  7,  is  of  the  type  of  that  given  by 
the  author  of  the  species,  and  that  of  the  dorsal  valve,  fig.  8,  is  not  very 
dissimilar,  although  representing  what  may  prove  to  be  a  distinct  species. 

Formation  and  localities. — Lower  portion  of  the  Pogonip  Group,  and 
upward  about  1,000  feet  on  the  east  slope  of  ridge  east  of  the  Hamburg 
mine;  on  the  second  ridge  southeast  of  the  Jackson  mine,  also  northeast  of 
Adams  Hill ;  on  the  ridge  southeast  from  the  Wood  Cone ;  at  the  south- 
west end  of  McCoy's  Ridge,  and  on  the  west  side  of  Goodwin  Canon,  Eureka 
District,  Nevada. 

LAMELLIBRANCHIATA. 

Geiius  TELLINOMYA  Hall. 

Tellinomya  contracts  Salter  (?) 

Plate  xi,  tig.  15,  15  a. 

Ctenodonta  contracta  Salter,  1859.     Canadian  Organic  Remains,  Dec.,  i,  p.  37,  pi.  viii, 
figs.  4,  5. 

It  is  not  improbable  that  the  Nevada  shell  is  specifically  unlike  T. 
contracta,  but  with  the  specimens  at  hand  it  is  difficult  to  determine  the 
differences  if  they  exist.  Mr.  Billings  has  described  a  closely  allied  form 
from  the  Quebec  series  of  Newfoundland,  but  our  species  is  more  nearly 
related  to  Salter's  species  from  the  Trenton  limestone  of  Canada,  to  which, 
for  the  present,  it  is  referred. 

Formation  and  locality. — Upper  part  of  Pogonip  Group,  Fish  Creek 
Mountains,  Eureka  District,  Nevada.  It  also  occurs  at  the  same  horizon  on 
Pogonip  Ridge,  White  Pine  District,  Nevada. 

Tellinomya  ?  Hamburgensis  n.  sp. 
Plate  xi,  figs.  1,  1  a. 

Shell  small,  thin,  convex;  rounded  subrhomboidal  in  outline  with  the 
height  and  width  subequal;  beak  elevated,  incurved,  and  raised  above  the 
hinge  line  anterior  to  the  center  of  the  shell. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


i  i 


The  surface  presents  a  smooth,  glistening  appearance,  and  is  marked 
by  fine  concentric  striae  and  very  fine,  often  scarcely  perceptible  radiating 
striae.  This  surface  gives  to, fragments  of  the  shell  the  character  of  some 
of  the  Linguloid  shells. 

The  species  belongs,  by  its  general  form,  to  the  group  of  which  T. 
(Ctenodonta)  varicosa  Salter  (Mem.  Geol  Surv.  Gt.  Brit,  vol.  iii,  p.  345)  and 
T.  (C )  astartceformis  Salter  (Can.  Org.  Remains,  dec.  1,  p.  39,  pi.  viii,  fig.  7) 
are  the  types;  specifically  it  is  distinct. 

Formation  and  locality. — Upper  part  of  Pogonip  Group.  East  slope  of 
ridge  east  of  the  Hamburg  Ridge,  Eureka  District,  Nevada. 


Genus  MODIOLOPSIS  Hall. 

Modiolopsis  occidens,  n.  sp. 
Plate  i,  fig.  5;  pi.  xi,  figs.  14,  14 a. 

Shell  small,  elongate,  ovate  in  outline;  broadest  at  the  posterior  half, 
contracting  to  about  two-thirds  the  greatest  width  at  the  beaks;  hinge-line 
nearly  straight  and  a  little  more  than  half  as  long  as  the  shell  posterior  to 
the  beaks;  posterior  margin  slightly  convex  and  sloping  obliquely  from  the 
extremity  of  the  hinge-line  to  the  rounded  posterior  end  of  the  shell;  the 
basal  line  curves  downward,  and  then  with  a  slight  sinuosity,  opposite  the 
beak,  extends  nearly  straight  to  the  somewhat  narrow,  sharply  rounded, 
anterior  end;  beak  small,  scarcely  extending  above  the  hinge-line,  and  sit- 
uated within  the  anterior  third  of  the  shell.  The  surface  is  moderately 
convex,  most  prominent  along  the  posterior  umbonal  ridge,  whioh  is  rather 
broadly  rounded;  umbonal  slope  abrupt  and  slightly  convex  A  broad, 
obscure  mesial  depression  is  shown  on  the  lower  part  of  the  anterior  half  of 
the  shell  that  does  not  extend  up  to  the  beak. 

Anterior  muscular  scar  of  medium  size  and  well  defined;  posterior 
scar,  pallial  line,  and  exterior  surface  markings  unknown. 

This  species  is  related  to  Modiolopsis  mytiloides  Hall  (Pal.  N.  Y.,  vol. 
i,  p.  157,  pi.  xxxv,  figs.  4  a,  b]  in  its  general  outline,  but  differs  in  its  less 
elongate  form  and  in  its  position  of  its  beaks. 

Formation  and  localities. — Pogonip  Group,  upper  portion,  Fish  Creek 


78  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Mountains,  Eureka  District,  and  beneath  the  white  quartzite  at  Lone  Moun- 
tain, 18  miles  northwest  of  Eureka,  Nevada.  It  also  occurs  at  the  same 
horizon  on  Pogonip  Ridge,  White  Pine  District,  Nevada. 

Modiolopsis  Pogouipensis,  n.  sp. 
Plate  i,  fig.  6 ;  pi.  xi,  fig.  13. 

Shell  quite  small,  ovate  in  outline,  broadest  at  the  posterior  third;  hinge- 
line  two-thirds  the  length  of  the  shell  posterior  to  the  beak;  posterior  mar- 
gin very  oblique,  slightly  convex,  and  terminating  at  the  somewhat  sharply 
rounded  posterior  extremity  of  the  shell;  basal  margin  slightly  curved, 
almost  straight  along  the  center;  anterior  end  of  the  shell  broadly  rounded. 
General  surface  moderately  convex,  most  prominent  along  the  rounded 
posterior  umbonal  ridge;  the  beak  is  strong  and  rises  a  little  above  the 
hinge-line ;  anterior  muscular  scar  distinct ;  posterior  scar  unknown. 

Surface  smooth  or  marked  by  broad  inconspicuous  lines  of  growth. 

Formation  and  localities. — Same  as  preceding  species. 

GASTEROPODA. 

Genus  RAPHISTOMA  Hall. 

Raphistoma  Nasoni  Hall. 

Plate  xi,  figs.  21,  21  a. 

Pleurotomaria  nasoni  Hall  (?)  1861.    Kep.  Prog.  Geol.  Surv.  Wisconsin,  pain.,  p.  34. 
Baphistoma  (Pleurotomaria)  nasoni  Hall,  1862.    Geol.  of  Wisconsin,  vol.  i,  p.  39,  fig.  2» 
Raphistoma  Nasoni  Whitfield,  1883.    Geol.  of  Wisconsin,  vol.  iv,  p.  215,  pi.  vi,  figs.  2-3. 

The  Nevada  shell  is  a  closely  allied  or  representative  species  of  this, 
and  in  its  condition  as  a  cast  it  is  impossible  to  give  any  good  specific  dif- 
ferences between  them.  It  might  be  considered  a  distinct  form  from  its 
occurring  at  so  distant  a  locality  and  at  a  lower  geologic  horizon,  but 
these  circumstances  are  largely  negatived  by  the  facts  that  well-character- 
ized Devonian  species  occur  in  New  York  and  Nevada  and  at  different 
relative  horizons,  as  will  be  shown  under  the  head  of  the  Devonian  fossils; 
and  species  heretofore  considered  as  belonging  to  the  Trenton  horizon  have 
been  identified  in  the  Pogonip  limestone,  e.  g.,  Orthis  testudinaria,  0.  trice- 


FOSSILS  OF  THE  LOWER  SILURIAN.  7& 

naria,  etc.  Under  such  circumstances  we  prefer  to  refer  all  such  species 
to  described  forms  unless  they  show  good,  specific  differences,  or  a  dif- 
ference in  their  geologic  horizon  that  renders  their  occurrence  extremely 
improbable. 

Formation  and  locality. — About  1,000  feet  down  in  the  Pogonip  Group, 
north  slope  of  White  Mountain,  Eureka  District,  Nevada. 


Genus  MURCHISONIA  D'Archiac  and  De  Yerneuil. 

Murchisonia  Milleri  Hall? 
Plate  i,  figs.  12,  12  a,  b. 

Murchisonia  bicincta  Hall,  1847.    Pal.  N.  Y.,  vol.  i,  p.  177,  pi.  xxxviii,  figs.  5,  5  a-h. 

Mcincta  Salter,  1858.    Canadian  Organic  Remains,  dec.  i,  p.  19,  pi.  ivr 

figs.  5,  6,  7. 

bicincta  M.  &  W.  ?,  1868.    Geol.  Surv.  Illinois,  vol.  iii,  p.  317,  pi.  iii,  fig  4. 
Milleri  Hall,  1877.    Cat.  Auier.  Pal.  Fossils,  Miller,  p.  244. 
Not  Murchisonia  bicincta  McCoy,  1844.     Syn.  Sil.  Foss.     Ireland,  p.  16. 

On  comparing  specimens  of  Murchisonia  Milleri,  from  Middleville,  New 
York  the  typical  locality  of  the  species,  with  the  Nevada  shell,  certain  differ- 
ences appear  that  would  serve  to  separate  the  form  from  Nevada  as  a 
distinct  species  from  M.  Milleri  if  the  range  of  variation  in  the  specimens 
from  the  two  localities  did  not  afford  examples  from  each  that  are  specifi- 
cally identical.  As  compared  with  the  majority  of  the  New  York  and 
Canadian  specimens,  the  Nevada  shell  is  more  depressed,  the  aperture  less 
elongate,  and  the  carina  above  and  below  the  peripheral  carina  less  strongly 
marked,  differences,  however,  that  are  not  apparent  when  comparing  with 
some  shells  from  the  typical  locality  at  Middleville;  with  this  in  view,  and 
the  fact  that  a  certain  range  of  variation  may  be  allowed  for  changes  pro- 
duced during  the  geographic  distribution  of  the  species,  I  think  we  are 
justified  in  identifying  the  Nevada  shell  with  M.  Milleri.  It  is  associated 
with  common  Trenton  limestone  fossils,  Orthis  tricenaria,  O.  perveta,  Raph- 

istoma  Nasoni,  lllcenus  crassicauda,  and  other  species  indicating  the  Trenton 
fauna. 

Formation  and  locality. — Lower  Silurian,  near  the  summit  of  the  Pogo- 
nip limestone  of  Pogonip  Ridge,  White  Pine  District,  Nevada. 


80  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Casts  of  two  species  of  Murchisonia  occur  in  the  upper  beds  of  the 
Pogonip  Group  of  the  Eureka  District.  One  is  slender,  elongate,  and 
formed  of  many  whorls,  resembling  the  eastern  species  Murchisonia  gracilis 
Hall  (Pal.  N.  Y.,  vol.  i,  p.  181,  pi.  xxxix,  figs.  4«-c) ;  the  other  is  a  much 
larger,  stronger  species,  more  like  Murchisonia  bellicincta  of  the  Trenton  lime- 
stone of  New  York.  The  specific  relations  of  either  are  not  determined. 

Genus  PLEUROTOMARIA  Defiance. 

Pleurotomaria  Lonensis,  u.  sp. 
Plate  xi,  fig.  22. 

Shell  rather  small,  depressed  conical;  the  apical  angle  about  110°; 
volutions  three  or  four,  each  flattened  above  to  within  a  short  distance  of 
the  sharp  mesial  angle,  where  a  narrow  groove  extends  around  on  the  lower 
volution,  becoming  obsolete  on  the  second  volution;  suture  in  the  cast  strong 
and  channeled;  lower  side  of  body  volution  sloping  quite  rapidly  in  from 
the  mesial  angle,  a  little  concave  just  within  the  angle,  and  then  gently  con- 
vex to  the  umbilicus,  which  is  rather  small.  Aperture  rhombic-subquadrate, 
as  far  as  can  be  determined  from  the  form  of  the  body  volution. 

Surface  unknown  except  by  the  presence  of  rather  strong  revolving 
lines  on  the  lower  side  of  the  body  volution. 

This  species  is  distinct  from  any  known  to  us. 

At  the  same  horizon  and  localities  there  is  another  species  that  may  be 
referred  to  this  genus;  it  is  a  larger  and  more  robust  form,  having  the  whorls 
more  convex  above,  flattened  below  on  the  body  volution,  and  an  acutely  an- 
gular periphery  at  the  union  of  the  upper  slope  of  the  whorls  and  the  base; 
this  latter  feature  also  occurs  in  P.  Lonensis. 

Formation  and  localities. — Upper  beds  of  the  Pogonip  Group,  Lone 
Mountain,  18  miles  northwest  of  Eureka;  at  the  south  end  of  Fish  Creek 
Mountain  exposure  of  the  Pogonip,  and  on  east  slope  of  ridge  east  of  Ham- 
burg mine,  Eureka  District,  Nevada. 

On  the  north  end  of  Pogonip  Ridge,  White  Pine  District,  Nevada,  this 
species  is  abundant  and  reaches  a  larger  size  than  at  Lone  Mountain. 


FOSSILS  OF  THE  LOWEE  SILURIAN. 


81 


Genus  HELICOTOMA  Salter. 

Helicotoma  sp.  f 

The  specimens  illustrating  this  species  are  badly  crushed,  but  there  is 
sufficient  form  preserved  to  show  that  it  is  allied  to  H.  planulata  Salter  (Cana- 
dian Organic  Remains,  dec.  i,  p.  14,  pi.  ii,  figs.  5-7)  and  H.  uniangulata  Hall 
(Pal.  N.  Y.,  vol.  i,  p.  179,  pi.  xxxviii,  fig.  8).  It  is  interesting  from  its  occur- 
rence at  an  horizon  between  those  of  the  two  species  mentioned.  The  first 
being  from  the  Calciferous  sandstone  of  New  York,  and  the  second  from  the 
Trenton  limestone  of  Canada. 

Formation  and  localities. — Upper  beds  of  Pogonip  Group.  Lone  Moun- 
tain, 18  miles  northwest  of  Eureka,  and  summit  of  White  Mountain,  Eureka 
District,  Nevada. 

Genus  MACLUEEA  Le  Sueur. 

Maclurea  annulata,  n.  sp. 
Plate  xi,  figs.  19,  19  a. 

Shell  quite  small,  subdiscoidal,  varying  from  10mm  to  12mm  in  the 
greatest  diameter;  spire  depressed  so  as  to  form  a  false  umbilicus;  lower 
side  flattened,  the  whorls  all  on  one  plane.  Volutions  about  two,  increas- 
ing rapidly  in  size  with  the  increase  in  growth  of  the  shell;  flattened  on  the 
under  side,  rounded  or  subangular  on  the  lower  periphery;  the  sides  rather 
steep ;  transverse  section  of  the  outer  volution  semiovate. 

Surface  of  the  shell  somewhat  strongly  annulated,  the  annulations  on 
the  outer  volution  having  a  breadth  of  about  1.5™*. 

Casts  of  this  species  show  the  shell  to  have  been  quite  thick,  and  a 
fragment  of  the  outer  volution  is  near  0.75mm  in  thickness.  The  annulations 
and  the  constrictions  between  are  strong,  but  owing  to  the  thickness  of  the 
shell  no  perceptible  traces  of  them  are  preserved  on  the  internal  cast. 

The  cast  is  more  angular  on  the  lower  outer  margin  than  on  the  upper 
margin;  it  bears  a  strong  resemblance  to  M.  minima  H.  and  W.  (Geol.  Expl. 
Fortieth  Par.,  vol  iv,  p.  235,  pi.  i,  figs.  17-19),  in  this  condition,  but  varies 
in  the  greater  depth  of  the  whorls  and  the  more  rapidly  increasing  size  of 
the  inner  whorls  of  M.  minima. 
6  c  D  w 


82  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Formation  and  localities. — Strata  of  the  Pogonip  Group,  north  slope  of 
White  Mountain,  500  feet  below  the  summit;  east  slope  of  ridge  east  of  the 
Hamburg  mine,  Eureka  District,  Nevada,  The  species  also  occurs  at  the 
same  horizon  on  Pogonip  Ridge,  White  Pine  District,  Nevada. 


Maclurea  subannulata,  n.  sp. 
Plate  xi,  figs.  18,  18  a- 6. 

Shell  about  twice  the  size  of  the  preceding  species  and  presenting  all  its 
essential  features  of  a  flat  lower  surface  and  deeply  umbilicate  or  depressed 
upper  side.  It  differs  in  the  more  rapidly  increasing  size  of  the  volutions, 
their  more  elongate  semioval  section,  more  rounded  periphery,  and  in  the 
cast  being  obscurely  annulated  but  in  a  reverse  manner  from  what  would 
be  the  case  if  the  annulations  of  the  outer  shell  of  M.  annulata  were  present 
on  the  cast;  the  constrictions,  instead  of  being  narrow,  are  quite  broad  and 
the  annulations  narrow. 

Formation  and  locality. — Pogonip  Group,  north  slope  of  White  Mountain, 
Eureka  District,  Nevada. 

.> 

Maclurea  carinata,  n.  sp. 
Plate  xi,  figs.  20,  20  a. 

Shell  small,  general  form  thick,  discoidal;  greatest  diameter,  20mm; 
height  of  outer  whorl,  6mm;  spire  depressed  to  form  a  broad,  shallow,  um- 
bilical-like  area;  lower  side  nearly  flat,  or  with  a  slight  umbilical  depression 
of  the  inner  whorl;  volutions  about  three,  increasing  very  regularly  in  size 
with  the  growth  of  the  shell;  slightly  convex  on  the  lower  side,  terminating 
in  a  decided  carina  on  the  periphery,  where  it  unites  with  the  slope  of  the 
side;  the  sides  of  the  whorl  are  steep,  and  equal  in  depth  to  the  width,  the 
carina  at  the  lower  outer  margin  of  the  inner  whorls  resting  in  the  sutures 
of  the  umbilical  side. 

Surface  of  the  lower  sides  of  the  whorls  marked  by  numerous  strong 
striae  that  arch  across  the  whorl  and  forward  over  the  carina;  their  course 
on  the  upper  side  has  not  been  observed. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


83 


The  cast  of  the  outer  whorl  is  round-oval  in  outline,  the  shell  being 
thick  and  forming  the  carina  seen  on  the  outer  surface.  The  presence  of 
the  basal  carina  distinguishes  this  species  from  any  described  form. 

Formation  and  locality. — Upper  beds  of  the  Pogonip  Group  at  Lone 
Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

Interior  casts  of  a  species  allied  to  this,  and  it  may  be  the  same,  occur  on 
White  Mountain  and  the  lower  eastern  slope  of  the  ridge  east  of  the  Ham- 
burg mine,  and  at  the  same  horizon  on  the  Fish  Creek  mountains,  Eureka 
District,  Nevada. 

Maclurea,  sp.  ? 

Associated  with  the  preceding  at  Lone  Mountain  there  is  a  cast  of  a 
much  larger  and  unusually  flattened  or  compressed  species.  Owing  to  a 
doubt  of  this  being  its  natural  form,  it  was  omitted  in  selecting  specimens 
for  illustration.  In  general  form  it  is  not  unlike  M.  acuminata  Billings 
(Pal.  Foss.,  vol.  i,  p.  241,  fig.  225,  1865),  except  that  it  is  very  shallow,  not 
one-half  the  depth  of  the  latter. 


Genus  METOPTOMA  Phillips. 

Metoptoma  Phillips!,  n.  sp. 
Plate  i,  figs.  4,  4  a. 

General  form  of  shell  depressed  conical;  outline  of  base  broadly 
elliptical  to  ovate:  apex  elevated  and  situated  a  little  behind  the  anterior 
margin;  sides  gently  convex  or  sloping,  almost  straight  from  the  apex  to 
the  lateral  margins ;  anterior  slope  from  the  apex  to  the  margin  slightly  con- 
cave; posterior  slope,  from  the  apex  to  the  posterior  margin,  broadly  convex. 

Surface  marked  by  fine  concentric  striae  of  growth,  with  a  few  stronger 
striae,  or  lines,  at  irregular  intervals. 

Dimensions:  greater  diameter  of  base  of  large  specimen,  23mm;  lesser 
diameter,  17mm;  height  of  apex  above  base,  10mm.  A  small  specimen  gives 
8mm  and  6mm  for  the  two  diameters  of  the  base,  and  3mm  as  the  height,  show- 
ing that  the  relative  proportions  remain  nearly  the  same  in  the  young  shells. 

I  know  of  no  closely  related  American  or  European  species.  Mr.  Bil- 
lings has  described  a  number  of  species  from  the  Quebec  and  Trenton 


84  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Groups  of  Canada,  but  owing  to  the  few  salient  characters  to  notice  in  a 
description,  and  the  entire  lack  of  illustration,  it  is  impossible  to  make  spe- 
cific identifications.  The  most  nearly  related  species  with  which  I  am 
acquainted  are  Metoptoma  Trentonensis  Billings  (Pal.  Foss.,  vol.  i,  p.  40,  fig. 
41,  1865),  and  M.  perovalis  Whitfield  (Geol.  Surv.  Wis.,  vol.  iv,  p.  211,  pi. 
v.  figs.  13,  14,  1883),  from  the  Trenton  limestone. 

Formation  and  locality. — Lower  Silurian,  near  the  summit  of  the  Pogonip 
limestone,  Pogonip  Ridge,  Eureka  District,  Nevada. 

Metoptoma  ?  analoga,  n.  sp. 
Plate  i,  figs.  11,  11  a. 

Shell  subconical,  patelliform;  outline  of  base  broadly  elliptical;  apex 
elevated,  subcentral,  and  bending  slightly  to  one  side. 

Surface  marked  by  slightly  defined  undulations  of  growth. 

Dimensions. — Base,  greater  diameter,  11 mm;  lesser  diameter,  9mm;  height 
of  apex  above  base,  6mm. 

This  somewhat  irregular  shell  occurs  at  the  same  geologic  horizon  as 
M.  Phillipsi,  but  not  in  the  same  stratum  of  rock.  It  is  a  well-marked 
species,  approaching  the  common  form  of  a  true  patella  more  than  the  forms 
usually  referred  to  Metoptoma.  As  with  all  generic  references  of  the  Pale- 
ozoic patelloid  shells,  when  the  interior  muscular  scars  are  unknown,  it  is 
more  or  less  arbitrary. 

Formation  and  locality. — Lower  Silurian,  near  the  summit  of  the  Pogonip 
limestone,  Pogonip  Ridge,  Eureka  District,  Nevada. 

Genus  CYETOLITES  Conrad. 
Cyrtolites  sinuatus  H.  &  W. 

Cyrtoliies  sinuatus  Hall  &  "W  bitfield,  1877.    Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  237, 
pi.  i,  figs.  23,  24. 

The  type  of  this  species  is  from  the  Pogonip  limestone  of  Pogonip 
Mountain,  in  the  White  Pine  Mining  District,  Nevada.  It  also  occurs  in 
the  upper  beds  of  the  same  group  at  Lone  Mountain,  18  miles  northwest  of 
Eureka,  Nevada. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


85 


PTEROPODA. 
Genus  COLEOPRION  Sandberger. 

Coleoprion  minuta,  n.  sp. 
Plate  xi,  figs.  17,  17 a;  pi.  xii,  fig.  21. 

Minute,  slender,  elongate  subcylindrical  tubes;  slightly  curved,  with  a 
distinct  angularity  on  the  outer  side,  section  subelliptical.  Average  length, 
8mm  to  10mm;  average  diameter,  1.25mm  at  smaller  end  to  2.25mmat  larger  end. 

Surface  marked  by  fine  annulations,  with  very  fine  concentric  striae 
between,  the  latter  perceptible  only  under  favorable  conditions.  The  annu- 
lations are  narrow,  rather  sharp,  and  cross  the  inner  side  of  the  curvature  of 
the  tube  transversely,  bending  obliquely  backward  on  each  side,  and  meet- 
ing at  an  angle  on  the  slight  ridge  on  the  outer  side. 

This  interesting  little  species  is  probably  a  true  Coleoprion,  although 
presenting  some  differences  from  the  typical  species ;  .these,  however,  appear 
to  be  rather  of  specific  than  generic  value. 

M.  Barrande  describes  one  species  from  the  Upper  Silurian  (J&tage  E], 
and  one  from  the  Devonian,  at  which  horizon  all  other  species  referred  to 
the  genus  have  been  obtained.  Its  range  is  now  extended  down  to  the 
horizon  of  the  Chazy  limestone  of  the  New  York  series,  or  the  summit  of 
the  Pogonip  Group  of  Nevada. 

Formation  and  locality. — Upper  Pogonip  limestone  of  Lone  Mountain, 
18  miles  northwest  of  Eureka,  Nevada,  and  at  the  same  horizon  on  Pogo- 
nip Ridge,  White  Pine  District,  Nevada. 


Genus  HYOLITHES  Eichwald. 

Hyolithes  Vanuxemi,  n.  sp. 

Plate  xi,  figs.  16,  16  a,  6. 

Form,  a  slender,  elongate,  subtriangular  tube,  with  the  lateral  margins 
rounded,  gradually  tapering  from  the  base  to  an  acute  extremity.  Trans- 
verse section  semi-elliptical,  almost  flat  on  the  ventral  side,  the  lateral  edges 
rounded  or  subtriangular.  Ventral  face  nearly  flat  transversely  and  in- 


86  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

curved  longitudinally ;  dorsal  face  strongly  convex  and  obtusely  angular 
along  the  center  in  some  examples.  Form  of  the  aperture  unknown. 

Surface  with  fine  transverse  striae  on  the  ventral  and  dorsal  sides  along 
the  central  portion  of  the  tube :  these  were  not  observed  towards  the  aper- 
ture. 

Length  of  larger  examples,  20mm;  greatest  width,  2.75mm;  depth,  2mm. 

This  species  is  distinguished  by  its  slender  elongate  form  with  the  sub- 
triangular  section  from  any  described  form  known  to  me. 

Formation  and  locality. — Lower  beds  of  the  Pogonip  Group,  northeast 
of  Adams  Hill,  Eureka  District,  Nevada. 


CEPHALOPODA. 
ORTHOCERATA. 

Plate  xii,  figs.  1,  1  a-c,  2,  and  3. 

Numerous  fragments  of  Orthoceratites  occur  in  the  upper  beds  of  the 
Pogonip  Group  at  Lone  Mountain  and  the  Fish  Creek  Mountains.  From 
among  them  several  well-defined  species  may  be  selected. 

1.  Endoceras  proteiforme  Hall?  (Pal.  N.  Y.,  vol.  i,p. 208, 1847) ;  plate  xii,  figs.  1,1  o-c. 

This  is  the  most  abundant,  and  is  found  at  the  principal  exposures  of 
the  upper  portion  of  the  group,  and  the  transverse  sections  (fig.  la)  are 
often  seen.  In  fig.  1  the  siphuncle  with  an  inner  tube  is  shown,  and  fig. 
1  c  shows  the  annulations  on  the  outer  surface  of  the  siphuncle. 

2.  Orthoceras  multicameratum  Hall?  (Pal.  N.  Y.,  vol.  i,  p.  45, 1847);  plate  xii,  tig.  3. 

The  fragment  illustrated  on  plate  xii,  fig.  3,  and  also  several  not  figured, 
shows  a  form  closely  allied  to  the  species  from  the  Birdseye  limestone  of 
New  York;  with  the  exception  of  the  tube  not  converging  as  rapidly  to- 
wards the  apex  the  specific  resemblance  is  very  strong. 

3.  Orthoceras  sp.  ?  plate  xii,  fig.  2. 

An  elongate  form  of  the  type  of  the  preceding  species.  The  material 
representing  it  is  so  fragmentary  that  a  specific  identification  is  not  at- 
tempted. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


87 


4.  Endoceras  multitubulatum  Hall?  (Pal.N.  Y.,  vol.i,  p.  59, 1847). 

Several  elongate  tubes  filled  in  with  smaller  tubes,  as  in  E.  multitubula- 
tum,  occur  in  the  upper  beds  of  the  Fish  Creek  Mountain  Pogonip,  and  simi- 
lar specimens  were  observed  a  little  lower  in  the  group  at  White  Mountain. 
They  belong  to  the  same  group  of  species  as  E.  multitubulatum,  but  in  the 
fragmentary  condition  of  the  specimens  it  is  impossible  to  state  that  they 
are  specifically  identical  with  the  Trenton  species. 

5.  Orthoceras  sp.  ?  plate  xii,  fig.  1  b. 

This  is  a  transverse  section  of  a  tube  showing  a  peculiar  siphuncle  and 
inner  tube.  As  the  figure  on  the  plate  does  not  give  the  desired  repre- 
sentation, figures  are  here  introduced  that  show  a  slightly  oblique  section  at 
each  end  of  a  tube  10mm  in  length. 

The  inner  tube  (s)  is  subcentral  with  a  broad  extension  (e)  from  one 
side  nearly  to  the  side  of  the  tube  next  outside  of  it  (#), 
and  on  the  opposite  side  a  thin  septum  (c)  projects  towards 
the  side  of  the  tube.  A  longitudinal  view  of  the  tube  (s) 
shows  it  to  be  straight  and  without  annulations.  Viewing 
the  specimen  as  complete  with  the  tubes  (s)  and  (#),  we 
find  it  to  be  closely  allied  to  a  section  given  of  Orthoceras 
bonum  by  Barrande,7  but  if  the  outer  shell  (0)  belongs  to  the 
Nevada  shell  and  is  not  a  fragment  into  which  the  tube  (x)  was  drifted, 
then  the  peculiar  section  is  not  explained  by  any  described  species  known 
to  me,  as  it  would  be  much  as  is  represented  by  the  fig.  1  b  of  plate  xii,  and 
be  formed  of  three  tubes,  one  within  the  other. 

Future  exploration  and  the  discovery  of  more  material  will  undoubt- 
edly afford  the  paleontologist  the  means  of  identifying  this  and  several 
other  species  now  recognized  by  fragments  too  imperfect  for  description  but 
still  specifically  distinct  from  each  other  and  the  species  we  have  mentioned. 
The  fragmentary  remains  now  before  us,  however,  with  the  associated 
Brachiopods,  Lamellibranchs,  and  Gasteropods  serve  the  present  purpose  of 
the  geologist,  as  they  indicate  the  passage  from  the  Pogonip  (Quebec)  to 
the  Trenton  fauna. 


FIG.  2. 


7  Syst.  Sil.  Boh&me,  vol.  ii,  pi.  ccxlvii,  fig.  11. 


88  PALEONTOLOGY  OF  THE  EUBEKA  DISTRICT. 

CRUSTACEA. 
Genus  LEPEEDITIA  Eonalt 

Leperditia  bivia  White. 

Leperditia  bivia  White,  1874.     Expl.  and  Surv.  West  100th  Merid.    Prelim.  Notice 
Invert.  Foss.,  p.  11  j  ibid.,  vol.  iv,  pt.  1,  p.  58,  pi.  iii,  figs.  7o-d,  1875. 

This  species  is  very  abundant  in  the  upper  beds  of  the  Pogonip  Group, 
at  Lone  Mountain,  18  miles  northwest  of  Eureka,  White  Mountain,  and  the 
Fish  Creek  Mountains,  Eureka  District,  Nevada. 

The  original  type  specimens  were  from  the  SchelKCreek  Range  of 
Nevada. 

Associated  with  this  species  we  find  two  smaller  species  not  unlike  some 
varieties  of  L.  Canadensis  (Can.  Organic  Remains,  dec.  iii,  p.  92,  pi.  xi,  figs. 
6,  7,  9,  10,  1858),  the  determination  and  illustration  of  which  is  left  for  fu- 
ture study. 

Genus  BEYEICH1A  McCoy. 
Beyrichia,  sp.  T 

This  is  an  interesting  species,  as  it  is  of  the  type  of  B.  regularis  Eni- 
mons  (Amer.  Geol.,  pt.  2,  p.  219,  1858),  of  the  Hudson  River  Group  of  Ohio. 

Owing  to  the  imperfect  condition  of  the  specimens  its  further  identifi- 
cation is  delayed  in  the  hope  of  obtaining  better  material.  It  is  associated 
with  Leperditia  bivia,  at  White  Mountain,  Eureka  District,  Nevada. 

Genus  PLUMULITES  Barrande. 

The  presence  of  this  rare  genus  in  American  strata,  west  of  Ohio,  has 
not  hitherto  been  recorded,  and  now  we  have  but  a  single  plate  to  show  it. 
This  is  triangular  in  its  general  form,  with  the  basal  margin  sigmoidal  and 
the  surface  ornamented  with  the  characteristic  lines  parallel  to  the  sigmoidal 
margin.  It  occurs  in  the  lower  portion  of  the  Pogonip  Group,  on  the 
southwest  end  of  McCoy's  Ridge,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


PCECILOPODA. 
Genus  DICELLOOEPHALUS  Owen. 

Dicellocephalus  finalis,  n.  sp. 
Plate  xii,  figs.  12,  12  a,  &. 

Form  of  glabella  and  fixed  cheeks  united,  very  irregular;  front  broadr 
rapidly  contracting  before  and  expanding  at  the  eyelobes  to  contract  again 
back  of  them.  Glabella  of  about  the  same  width  at  the  base  and  in  front, 
expanding,  on  the  posterior  half,  to  the  border  of  the  palpebral  lobes;  gen- 
eral surface  quite  convex  on  the  anterior  half  and  moderately  so  farther- 
back,  marked  by  three  pairs  of  glabellar  furrows;  the  anterior  pair  slightly 
impressed  and  short,  situated  opposite  the  anterior  end  of  the  eyelobes; 
the  median  pair  more  strongly  impressed  and  directed  obliquely  inward 
about  one-fourth  the  distance  across  from  side  to  side;  directly  back  of  this 
pair  the  margin  curves  outward  around  a  curved  expansion  of  the  glabella, 
and  within  this  the  posterior  pair  of  furrows  are  impressed,  similar  to  the 
median  pair,  but  not  reaching  the  outer  margin;  this  gives  the  posterior 
portion  of  the  glabella  a  very  peculiar  aspect,  unknown  in  any  other  species 
of  the  genus;  occipital  ring  broad  and  flattened;  occipital  furrow  narrow 
and  well  impressed;  dorsal  furrow  distinct,  but  very  shallow;  fixed  cheeks 
hardly  more  than  a  line,  except  where  they  join  the  broad  frontal  limb; 
palpebral  lobes  long  and  narrow;  postero-lateral  limbs  narrow  and  extended 
laterally;  frontal  limb  of  moderate  length,  gently  concave,  and  bordered 
by  a  strong  rounded  margin,  the  anterior  edge  of  which  is  broadly  rounded 
up  to  a  very  obtuse  angle  at  the  center.  * 

Thorax  known  only  by  fragments  of  the  segments  associated  with  the 
head  parts.  These  show  the  median  lobe  to  have  been  moderately  convex 
and  the  lateral  lobes  less  so ;  the  pleurae  are  straight  or  slightly  curved  two- 
thirds  the  way  out,  and  then  curved  backward  on  the  free  end;  pleural  groove, 
strongly  marked. 

The  associated  pygidium  is  moderately  convex,  with  a  conical  axial  lobe 
crossed  by  three  annulations,  besides  the  long  terminal  one;  lateral  lobes 


00  PALEONTOLOGY  OF  THE  EUKEKA  DISTEICT. 

indicating  four  coalesced  segments,  marked  by  pleural  grooves  and  termi- 
nating in  points  that  give  a  digitated  margin  to  the  pygidium. 

Surface  apparently  smooth. 

As  all  of  these  parts  occur  at  one  horizon  and  in  the  same  layer,  and 
no  other  large  trilobite  is  associated  with  them,  they  undoubtedly  belong  to 
one  species. 

Formation  and  localities. — In  the  lower  portion  of  the  Pogonip  Group, 
on  the  east  slope  of  the  ridge  next  east  of  the  Hamburg  Ridge,  Eureka 
District,  Nevada. 

Dicellocephalus  inexpectans,  n.  sp. 
Plate  i,  fig.  10. 

Glabella  quadrangular,  moderately  convex,  lateral  margins  parallel, 
broadly  rounded  in  front;  surface  marked  by  two  pairs  of  slightly  im- 
pressed glabellar  furrows  directed  obliquely  inward  and  backward ;  the 
occipital  ring  is  of  medium  width,  and  the  occipital  furrow  distinctly  but 
not  deeply  marked;  dorsal  furrows  clearly  defined  at  the  sides  and  front  of 
the  glabella;  fixed  cheeks  very  narrow,  sloping  rapidly  away  before  and 
behind  the  palpebral  lobe;  palpebral  lobes  prominent  and  of  medium  size; 
frontal  limb  rather  long  -arid  well  extended  laterally;  a  number  of  raised 
lines  radiate  from  the  front  of  the  glabella  to  the  frontal  margin;  frontal 
margin  narrow,  rounded ;  postero-lateral  limbs  unknown.  The  facial  sutures 
pass  very  obliqely  inward  from  the  anterior  margin  to  the  palpebral  lobe, 
giving  the  front  inclosed  within  them  a  campanulate  form;  curving  around 
the  palpebral  lobes  they  pass  outward  on  the  postero-lateral  limbs. 

Surface  finely  granulose. 

This  species  is  associated  in  the  same  horizon  with  D.  finalis  of  this 
report.  It  was  collected  one  year  after  the  latter  was  described  in  MSS. 
It  affords  another  illustration  of  a  Cambrian  type  continuing  into  the  Silu- 
rian and  mingling  with  its  fauna. 

Formation  and  localities. — Same  as  D.  finalis. 


FOSSILS  OF  THE  Lf.WEE  SILURIAN. 


91 


Genus  PTYCHOPARIA  Corda. 

Ptychoparia  .'  anuectans,  n.  sp. 
Plate  xii,  fig.  18. 

Head  very  small,  semicircular;  postero-lateral  angles  unknown.  Gla- 
bella  moderately  convex,  length  and  width  subequal,  broadly  rounded  in 
front;  marked  by  three  pairs  of  furrows,  the  anterior  pair  scarcely  per- 
ceptible, median  and  posterior  pairs  distinctly  but  not  deeply  impressed ; 
occipital  ring  narrow,  rounded,  without  a  spine;  occipital  furrow  well  de- 
fined; dorsal  furrow  narrow,  distinct,  and  extending  with  equal  force  in 
front  of  the  glabella ;  fixed  cheeks  rather  wide,  sloping  with  a  gentle  con- 
vexity to  the  minute  eyelobes  and  into  the  frontal  limb;  frontal  limb  con- 
vex, curving  rapidly  downward,  and  bordered  by  a  rounded  rim ;  postero- 
lateral  limbs  narrow,  and  extended  quite  a  little  distance  laterally,  marked 
by  a  narrow  groove  in  the  posterior  margin. 

Thorax  and  pygidium  unknown. 

This  little  species  is  closely  allied  to  P.  minutus  (Sixteenth  Ann.  Rep. 
N.  Y.  State  Cab.  Nat.  Hist.,  p.  150,  pi.  viii,  figs.  5-7,  1861)  of  the  Potsdam 
sandstone  of  New  York,  and  the  allied  P.  minor  (Ibid.,  p.  149),  from  the 
same  horizon  in  Wisconsin.  It  differs  in  the  shorter  glabella,  absence  of 
nuchal  spine,  and  larger  frontal  limb.  It  is  interesting  as  occurring  in 
association  with  the  preceding  species,  and  as  terminating  the  upper  limit 
of  the  range  of  the  genus  in  the  Prospect  Mountain  section. 

Formation  and  locality. — In  the  lower  portion  of  the  Pogonip  Group  on 
the  east  slope  of  the  ridge  next  east  of  the  Hamburg  Ridge,  Eureka  Dis- 
trict, Nevada. 


Genus  BATHYUEUS  Billings. 

Bathyurus  ?  tuberculatus,  n.  sp. 
Plate  xii,  fig.  9. 

Glabella  conical,  strongly  convex  and  elevated  above  the  fixed  cheeks ; 
occipital  segment  narrow,  elevated  on  the  posterior  margin,  and  with  a  short 
spine  projecting  backward  and  a  little  upward  from  the  center;  occipital 


92  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

furrow  rather  broad  and  strongly  impressed ;  fixed  cheeks  of  average  width, 
sloping  upward  from  the  strongly  marked  dorsal  furrows  to  the  eyelobes, 
falling  away  to  the  front  and  back;  frontal  limb  curving  abruptly  down- 
ward to  a  strong  rounded  rim-like  margin;  postero-lateral  limbs  strongly 
marked  by  a  furrow  within  the  posterior  margin. 

Surface  of  glabella  and  fixed  cheeks  ornamented  with  pustules,  finely 
granulose  in  the  narrow  interspaces. 

This  species  is  characterized  by  the  pustulose  surface  of  the  head.  No 
remains  of  the  thorax  or  pygidium  were  observed  in  association  with  the 
head  parts. 

Formation  and  locality. — Pogonip  Group,  on  the  ridge  southwest  of 
Wood  Cone,  Eureka  District,  Nevada,  and  at  the  same  horizon  on  the  north 
end  of  Pogonip  Ridge,  Eureka  District,  Nevada. 


Bathyurus  ?  congeneris,  n.  sp. 
Plate  xii,  fig.  8. 

Compare  Bathyurus  f  serratus  Meek,  1873.     Sixth  Aim.  Rep.  U.  S.  Geol.  Surv.  Terri- 
tories for  the  year  1872,  p.  480. 

General  outline  of  glabella  and  fixed  cheeks,  exclusive  of  the  postero- 
lataerl  limbs,  subquadrangular  and  rather  strongly  convex.  Glabella  ob- 
long, sides  nearly  parallel,  and  front  rounded.  Occipital  ring  of  moderate 
width,  and  separated  from  the  glabella  by  a  narrow,  well-impressed  furrow; 
dorsal  furrows  narrow  but  well  defined  on  the  sides  and  in  front  of  the  gla- 
bella; fixed  cheeks  of  medium  width,  somewhat  depressed  below  the  level 
of  the  glabella;  frontal  limb  as  a  narrow,  rounded  rim;  postero-lateral  limbs 
extended  laterally  and  with  a  narrow  furrow  within  the  posterior  margin. 

Surface  finely  granulose. 

An  illustration  is  given  of  the  pygidium  associated  with  the  glabella 
and  fixed  cheeks,  plate  xii,  fig.  8  a. 

This  species  is  closely  allied  to  Bathyurus  f  serratus  Meek,  and  Bathy- 
urus oblongus  Billings  (Pal.  Foss.,  vol.  i,  p.  411,  fig.  394,  1865),  the  chief 
difference  between  them  being  in  the  details  of  the  frontal  limb.  They  are 


FOSSILS  OF  THE  LOWER  SILURIAN. 


93 


congeneric,  but  whether  belonging  to  this  genus  or  not  it  is  difficult  to  deter- 
mine in  the  absence  of  the  thorax  and  pygidium. 

Formation  and  localities. — Pogonip  Group,  on  spur  southwest  of  Wood 
Cone  and  below  Bellevue  Peak,  Fish  Creek  Mountains,  Eureka  District, 
Nevada. 

Bathyurus  ?  simillimus,  n.  sp. 
Plate  xii,  fig.  11. 

This  species  is  closely  related  to  the  preceding  and  to  B.  oblongus 
Billings,  (Joe.  cit.  p.  92)  in  the  form  and  convexity  of  the  glabella  and  fixed 
cheeks;  the  frontal  limb,  however,  is  longer,  curved  more  abruptly  down- 
ward, and  bordered  by  a  rounded  rim  that  has  a  distinct,  very  obtuse  angu- 
larity in  front. 

The  surface  of  the  glabella  is  minutely  granulose. 

Formation  and  locality. — In  the  limestone  of  the  Pogonip  Group,  on  the 
north  slope  of  White  Mountain,  about  500  feet  from  the  summit  of  the 
mountain,  Eureka  District,  Nevada. 

The  pygidium,  illustrated  by  fig.  14  of  plate  xii,  is  of  the  same  type  as 
that  upon  which  Mr.  Billings  founded  the  species  Bathyurus  caudatus  (Pal. 
Foss.,  vol.  i.,  p.  261,  fig.  245,  1865),  which  occurs  in  the  Quebec  Group  of 
Newfoundland.  It  undoubtedly  belongs  to  a  distinct  species;  its  generic 
relations  are  not  recognized. 


Genus  CYPHASPIS  Burmeister. 

Cyphaspis  ?  brevimarginatus,  n.  sp. 
Plate  xii,  fig.  10. 

Glabella  conical,  strongly  convex,  marked  by  a  pair  of  posterior  gla- 
bellar  furrows  extending  obliquely  inward  so  as  to  nearly  separate  a  small 
lobe  at  each  postero- lateral  angle ;  occipital  segment  broadest  at  the  center 
narrowing  towards  the  dorsal  furrows;  occipital  furrow  well  defined;  dorsal 
furrows  distinctly  impressed  along  the  sides  of  the  glabella;  fixed  cheeks 
rather  narrow  midway,  widening  in  front;  frontal  limb  as  a  scarcely  per- 


94  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

ceptible,  depressed,  narrow  rim  in  front  of  the  glabella  and  fixed  cheeks; 
postero-lateral  limbs  unknown. 

Surface  of  glabella  minutely  granulose. 

This  species,  although  founded  on  a  glabella  but  4mm  in  length,  is 
clearly  distinguished  from  any  described  form  by  its  almost  obsolete  frontal 
margin  and  the  conical  outline  of  the  glabella. 

Formation  and  locality. — Pogonip  Group,  on  the  eastern  slope  of  ridge 
east  of  the  Hamburg  Ridge,  Eureka  District,  Nevada. 


Genus  AMPHION  Pander. 

Amphion  Nevadensis,  n.  ap. 
Plate  xii,  fig.  13. 

Glabella  subquadrangular,  slightly  convex,  sides  parallel,  front  broadly 
rounded ;  surface  marked  by  three  pairs  of  furrows,  the  two  posterior  pairs 
extending  obliquely  inward  about  one-third  the  entire  distance  across; 
anterior  pair  shorter  and  situated  so  far  forward  that  the  anterior  lobe  is 
somewhat  irregularly  rhomboidal  in  outline;  occipital  segment  strong,  flat- 
tened; occipital  furrow  narrow  and  like  the  dorsal  furrows,  deeply  impressed; 
fixed  cheeks  known  only  in  part;  they  are  narrow  in  front,  increasing  in 
width  at  the  eyelobes,  and  extending  backward  to  the  broad  strong  postero- 
lateral  limbs;  the  latter  are  strongly  marked  by  the  continuation  of  the 
occipital  groove  within  the  posterior  margin. 

Surface  granulose  as  far  as  can  be  determined  from  the  specimens, 
which  owing  to  exposure  are  somewhat  imperfect. 

Formation  and  localities. — Pogonip  Group,  upper  portion,  on  the  south- 
east slope  of  Bellevue  Peak,  Fish  Creek  Mountains,  Eureka  District, 
Nevada;  Amphion  Nevadensis  also  occurs  in  the  Upper  Pogonip  limestone  on 
the  north  end  of  Pogonip  Ridge,  White  Pine  District,  Nevada. 

Two  pygidise  occur  at  other  localities,  which  may  be  referred  to  this 
genus.  They  belong  to  different  species,  but  without  the  head  parts  a 
specific  determination  or  name  would  be  of  little  value. 


FOSSILS  OF  THE  LOWEE  SILURIAN. 


95 


Genus  CEEAUEUS  Green. 

Ceraurus?  sp.  undt. 
Plate  xii,  fig.  17. 

Glabella  subglobose,  marked  by  two  pairs  of  short  furrows  that  are 
only  seen  when  looking  from  the  sides;  occipital  segment  strong;  occipital 
furrow  well  defined,  also  the  dorsal  furrows;  fixed  cheeks  unknown  except 
a  fragment  near  the  dorsal  furrow.  Length  of  glabella,  3mm;  width,  3.25mm. 

This  curious  little  species  is  referred  to  the  genus  provisionally,  as 
without  other  parts  of  the  body  its  relations  are  not  readily  determined, 
and  on  the  same  account  the  specific  identification  is  not  attempted. 

Formation  and  locality. — Pogonip  Group,  lower  eastern  slope  of  ridge 
next  east  of  the  Hamburg  Ridge,  Eureka  District,  Nevada. 


Genus  SYMPHYSUEUS  Goldfuss. 

Symphysurus  ?  Goldfussi,  n.  sp. 
Plate  xii,  fig.  16. 

Glabella  subclavate,  convex,  marked  posteriorly  by  a  pair  of  short, 
lightly  impressed  furrows;  occipital  ring  strong  and  separated  from  the 
glabella  by  a  well-defined  but  not  deeply  impressed  furrow;  dorsal  furrows 
strong  but  shallow;  fixed  cheeks  of  medium  width,  rising  from  the  dorsal 
furrows  to  the  palpebral  lobes,  and  sloping  away  to  the  front  and  back; 
frontal  limb  very  short,  hardly  more  than  a  line  within  the  narrow  border; 
postero-lateral  limbs  but  little  extended  laterally,  and  marked  by  the  exten- 
sion of  the  occipital  furrow  across  their  posterior  side. 

Surface  apparently  smooth. 

This  species  is  referred  to  Symphysurus  on  account  of  the  subclavate 
glabella,  and  the  direction  of  the  facial  sutures.  In  the  absence  of  the 
thorax  and  pygidium  a  close  generic  reference  is  almost  impossible  with 
many  of  the  species  represented  only  by  fragments. 

Formation  and  locality. — Pogonip  Group,  on  the  west  slope  of  McCoy's 
Kidge,  Eureka  District,  Nevada. 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


Genus  BARRANDIA  McCoy. 

Barrandia  ?  McCoyi,  n.  sp. 
Plate  xii,  fig.  5. 

General  form  of  glabella  and  fixed  cheeks,  exclusive  of  the  extension 
of  the  postero-  lateral  limbs,  subquadrate.  Glabella  oblong,  widening  out  a 
little  towards  the  broadly  rounded  front;  general  surface  moderately  con- 
vex, and  unbroken  by  any  glabellar  furrows;  occipital  ring  of  average 
width;  occipital  furrow  distinct,  but  not  deeply  impressed;  dorsal  furrows 
quite  strong  in  the  specimen  illustrated,  and  less  so  in  other  examples; 
fixed  cheeks  of  average  width,  broadest  and  most  elevated  at  the  eyelobes 
from  which  they  slope  to  the  front  and  back;  eyelobes  situated  back  of  a 
line  uniting  their  anterior  margins  with  the  center  of  the  glabella;  the 
front  of  the  head  is  bordered  by  a  narrow,  flattened  rim;  postero-lateral 
limbs  triangular,  terminating  at  a  distance  from  the  dorsal  furrow  equal  to 
one-half  the  length  of  the  glabella  exclusive  of  the  occipital  ring. 

Surface  smooth  to  the  unaided  eye. 

After  an  examination  of  the  various  species  referred  to  this  genus  by 
Mr.  Salter,  we  find  that  the  Eureka  form  differs  from  most  of  them  in  the 
more  anterior  position  of  the  eyelobes  and  the  stronger  dorsal  furrows; 
features  that,  without  known  differences  in  the  thorax  and  pygidium  to  sup- 
port them,  we  do  not  consider  of  generic  importance.  As  the  parts  de- 
scribed, however,  are  all  that  is  known  of  the  species,  the  generic  reference 
is  somewhat  provisional  for  this  and  also  the  following  species. 

Formation  and  locality.  —  Pogonip  Group,  on  lower  eastern  slope  of  ridge 
•east  of  the  Hamburg  Ridge,  Eureka  District,  Nevada. 

Barrandia?  sp.  T 
Plate  xii,  fig.  6. 

Glabella  subclavate,  the  width  of  the  base  being  about  four-fifths  of 
that  of  the  anterior  portion;  front  broadly  rounded;  general  surface  gently 
convex,  curving  down  somewhat  abruptly  in  front  to  the  narrow,  rim-like 
margin;  occipital  ring  narrow  and  with  a  small  tubercle  at  the  center; 
occipital  furrow  shallow,  but  quite  distinct;  dorsal  furrows  clearly  defined. 


FOSSILS  OF  THE  LOWER  SILURIAN. 


97 


There  are  but  slight  traces  of  the  fixed  cheeks  attached  to  the  glabella. 
The  species  is  characterized  by  the  peculiarly  shaped  glabella. 

Formation  and  locality. — Pogonip  Group,  on  the  west  slope  of  McCoy's 
Ridge,  Eureka  District,  Nevada. 


Genus  ILL^NURUS  Hall. 

Illaenurus  Eurekensis,  n.  sp. 
Plate  xii,  fig8.  4,  4  a. 

Head  of  medium  width,  semi-elliptical;  glabella  subquadrate,  convex, 
a  little  longer  than  wide,  as  5  to  4,  with  scarcely  perceptible  occipital  or 
dorsal  furrows;  palpebral  lobes  nearly  central  on  the  margins;  frontal  mar- 
gin nearly  straight;  free  cheeks  a  little  longer  than  wide,  with  the  base  of 
the  eyes  cutting  into  them  about  the  middle  of  the  inner  margin;  genal 
angles  broadly  rounded. 

The  facial  suture,  cutting  the  frontal  rim  on  a  line  with  the  outer  edge 
of  the  eyelobe,  passes  directly  to  the  anterior  margin  of  the  eyelobe;  it 
encircles  that  and  then  curves  gently  outward  to  the  posterior  margin,  form- 
ing a  short,  triangular-shaped  lateral  limb. 

Surface  minutely  punctate. 

The  pygidiae  associated  with  the  head  parts  vary  very  much.  Two 
are  illustrated  on  plate  xii,  figs.  1 2  and  1 9,  neither  of  which  has  any  re- 
semblance to  the  pygidium  of  Illsenurus.  Another,  discovered  since  the 
plate  was  prepared,  shows  a  short,  smooth  axial  lobe,  slight  dorsal  furrows, 
and  gently  convex,  broad  lateral  lobes;  this  is  probably  the  pygidium  of 
this  species,  as  numerous  examples  of  the  glabella  occur  on  the  same  frag- 
ment of  rock. 

In  the  fourth  volume  of  the  Geology  of  Wisconsin  a  species  of  Illae- 
nurus, I.  convexus,  is  given  as  occurring  in  the  Lower  Magnesian  limestone 
of  that  State,  and  the  genus  is  also  represented  in  the  Potsdam  sandstone, 
Illoenurus  quadratus  Hall.  In  Nevada  as  yet  it  is  only  known  from  the 
horizon  above  that  representing  the  Potsdam,  or  the  correspondent  of  the 
Calciferous  formation  of  the  New  York  geologists. 

Formation  and  localities. — Lower  portion  of  the  Pogonip  Group,  on  the 
east  slope  of  the  ridge  east  of  the  Hamburg  Ridge;  on  second  ridge  south- 
7  o  D  w 


93  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

east  of  the  Jackson  mine;  a  little  to  the  northeast  of  Adams  Hill,  and  onr 
ridge  southwest  of  Wood  Cone,  Eureka  District,  Nevada.  In  the  White 
Pine  District,  Nevada,  it  was  found  in  the  central  portion  of  the  Pogonip 
limestone  on  Pogonip  Ridge. 

Genus  ASAPHUS  Brongniart. 

Asaphus  Caribouensis,  n.  sp. 
Plate  xii,  figs.  7,  7  a,  6. 

General  form  of  the  head  semi-elliptical,  moderately  convex;  glabella 
expanding  quite  rapidly  in  front  of  the  eyelobes  and  obtusely  angular  in 
front;  eyelobes  situated  back  of  a  line  uniting  their  anterior  margins  and. 
the  center  of  the  glabella;  postero-lateral  limbs  short  and  triangular  in  out- 
line. The  associated  free  cheek  is  a  little  longer  than  wide  and  with  a  dis- 
tinctly marked  border  and  genal  spine 

The  pygidise  occurring  in  the  same  hand  specimens  have  a  rather 
prominent  medium  lobe  and  smooth,  depressed  lateral  lobes,  without  traces- 
of  segments  on  the  latter. 

Formation  and  localities. — Pogonip  Group,  in  the  lower  portion  asso- 
ciated with  the  preceding  species,  and  also  in  the  upper  beds  at  the  west 
base  of  Caribou  Hill,  Eureka  District,  Nevada. 

Asaphus  ?  curiosa  Billings. 

Plate  xii,  fig.  15. 
Asaphus  ?  curiom  Billings,  1865.     Pal.  Foss.,  vol.  i,  p.  318,  fig.  305. 

This  curious  pygidium,  which  is  so  closely  allied  to  that  described  by 
Mr.  Billings  under  the  above  name,  shows  traces  of  annulations  on  the  me- 
dian lobe  when  the  outer  shell  is  removed.  Three  specimens  were  obtained, 
but  no  associated  parts  of  the  head  or  thorax. 

Fragments  of  two  other  species  of  Asaphus  occur  in  the  upper  layers 
of  the  Pogonip  Group.  One  from  Caribou  Hill  has  a  broad,  smooth,  planu- 
late  pygidium  with  a  very  small  and  short  median  lobe,  and  is  unlike  any 
species  known  from  American  strata,  being  allied  to  some  forms,  described 
by  Angelin,  from  Sweden.  The  other  species  is  related  to  A.  Caribouensis 


FOSSILS   OF   THE 

PORIFERA. 
Genus  PAL^EOMANON  Eoemer. 

Palasomanon  Roemeri,  n.  sp. 
Plate  xiii,  fig.  12. 

This  is  a  crateiform  or  cup-shaped  sponge  of  the  general  form  of  those 
referred  to  the  genus  Manon  of  the  Jurassic  and  Cretaceous,  and  for  the 
reception  of  the  Paleozoic  types  of  which  Dr.  Roemer  founded  the  genus 
Palseomanon,  making  P.  cratera  of  the  Niagara  Group  the  type. 

The  example  of  P.  Eoemeri  before  me  has  a  height  of  65mm,  and  a  diam- 
eter of.  oOmm,  contracting  below  to  form  a  rounded  base;  the  outer  wall 
extends  vertically  to  within  a  short  distance  of  the  summit,  where  it  curves 
inward  to  the  rounded  marginal  rim  of  the  shallow  cup;  this  has  a  depth  of 
15mm.  Owing  to  the  complete  silicification  and  change  of  the  original 
spiculae,  none  of  the  surface  characters  have  been  preserved;  the  unmis- 
takable, striking  form  serves  for  the  generic  and  specific  identification. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone  at 
Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


Genus  ASTYLOSPONGIA  Eoemer. 
Astylospongia,  sp.  ? 

Several  specimens  of  a  rather  small,  globose  or  flattened  oviform  sponge 
were  obtained  from  the  center  of  cherty  concretions.  The  largest  has  a 
diameter  of  30mra,  and  presents  in  a  transverse  section  numerous  fine,  radi- 
ating tubes  or  canals  studded  with  fine  spiculse.  Owing  to  the  imperfect 
preservation  of  all  the  specimens,  it  is  impossible  to  determine  their  specific 
relations  to  forms  already  described. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone  at 
Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

99 


100  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  STROMATOPORA  Goldfuss. 

One  or  two  species  of  this  genus  occurs  very  abundantly  at  several 
horizons  throughout  the  Devonian  formation.  They  are  not  in  a  condition 
to  admit  of  specific  determination  without  first  having  a  series  of  thin  sec- 
tions prepared  and  a  special  study  made  in  connection  with  other  species, 
the  material  for  which  is  not  available  at  present. 

ACTINOZOA. 

Owing  to  the  meagerness  of  the  material  representing  some  of  the  spe- 
cies, and  the  fact  that  much  larger  collections  may  be  obtained  for  future 
study,  it  is  not  considered  best  to  attempt  to  illustrate  and  describe  this 
group  until  it  can  be  done  in  a  more  satisfactory  manner  than  at  present. 
A  short  note  of  each  of  the  identified  species  and  a  notice  of  such  as  are  con- 
sidered new  and  undescribed  is  given.  The  specific  identifications  were 
chiefly  made  by  a  direct  comparison  of  the  Nevada  specimens  with  authen- 
ticated specimens  in  the  beautiful  and  extensive  collection  of  the  New  York 
State  Museum  and  the  private  collection  of  Prof.  James  Hall. 

Favosites  hemispherica  Yandell  and  Shumard.     See   Geol.    Surv.   Michigan,   vol.    iii,   pt.   2, 
p.  25,  1876. 

Several  specimens  of  the  cylindrical  form  of  growth  occur  in  the  collec- 
tions, but  none  of  the  large  hemispheric  or  turbinate  forms  so  characteristic 
of  the  species  in  the  Corniferous  limestone  of  New  York,  Ohio,  Canada,  etc. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone  at 
Lone  Mountain,  18  miles  northwest  of  Eureka,  and  also  at  the  head  of  the 
Reese  and  Berry  Canon,  Eureka  District,  Nevada. 

Pavosites  basaltica  Goldfuss.     1829.      Petref.  Germ.,  vol.  i,  p.  78. 

A  comparison  with  the  figures  given  by  Goldfuss,  and  also  with  a  speci- 
men from  Silesia,  shows  a  very  close  specific  resemblance  between  them 
and  the  Nevada  specimens,  and  one  of  the  latter  appears  to  be  specifically 
identical  in  all  its  characters  with  this  species.  Other  specimens  vary  in  the 
size  of  the  cells  from  2mm,  the  usual  size  of  those  in  F.  basaltica,  to  3mra; 
smaller  cells  not  over  lmm  in  diameter  occur  on  the  same  specimen.  In  the 
presence,  however,  of  a  single  row  of  pores  on  each  side  of  the  cells,  numer- 


FOSSILS  OF  THE  DEVONIAN. 


101 


ous  transverse  diaphragms,  the  general  size  of  the  cells,  and  the  mode  of 
growth,  the  species  is  similar  to  the  European  form  of  F.  basaltica. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone  at 
Lone  Mountain,  18  miles  northwest  of  Eureka;  at  the  head  of  the  Reese 
and  Berry  Canon,  and  on  the  ridge  of  Atrypa  Peak,  Eureka  District,  Nevada. 

Favosites,  n.  sp. 

Corallum  growing  in  hemispherical  or  irregularly  formed  masses  made 
up  of  small  tubes  varying  in  size  from  lmm  to  1.5mm,  which  are  without  any 
distinct  arrangement  in  relation  to  size,  the  smaller  cells  occurring  together 
or  with  the  larger  interspersed  among  them.  On  the  upper  surface  of  the 
corallum  the  cell  walls  are  thickened  and  have  a  beaded  appearance  which 
is  not  observed  in  a  transverse  section  of  the  tubes  a  short  distance  below 
where  the  walls  are  strong  and  the  tubes  distinctly  polygonal  and  not 
rounded  as  at  the  apertures.  Transverse  diaphragms  entire,  closely  ar- 
ranged or  separated  up  to  a  distance  equal  to  an  entire  diameter  of  the  tube 
Mural  pores  not  well  determined,  but  there  is  apparently  a  single  row  of 
rather  large  size  on  each  side. 

The  largest  fragment  obtained  has  a  depth  of  8cm,  and  the  diameter  of 
the  entire  corallum  was  from  15cm  to  20cm. 

In  the  character  of  the  cell -walls  at  the  surface  of  the  corallum,  the 
diaphragms  in  the  tubes,  and  form  of  growth,  this  species  is  not  unlike 
Favosites  f  Argus  Hall,  of  the  Hamilton  Group  of  New  York,  but  in  the 
small  size  of  the  cells,  and  the  absence  of  the  very  large  cells  among  the 
smaller  ones  in  the  latter  species,  it  is  very  distinct  from  it. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone  at 
Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

Fistulipora,  sp.  ? 

Silicified  specimens  of  a  well-characterized  species  of  this  genus  occur 
in  association  with  fossils  of  the  Upper  Helderberg  horizon.  Its  specific 
relations  are  not  yet  determined. 

Formation  and  locality — Devonian  limestone,  lower  horizon,  Atrypa 
Peak  Ridge,  Eureka  District,  Nevada. 


102  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Alveoiites  Rockfordensis  Haiif    1864.    Twenty-third  Ann.  Rep.  ]ST.  Y.  State  Cab.  Nat. 
Hist.,  p.  229. 

The  cell  apertures  open  more  directly  with  the  plane  of  the  surface  in 
the  Nevada  specimens  than  in  those  from  the  Chemung  Group  of  Iowa,  but 
otherwise  there  la  a  marked  specific  similarity  and  a  provisional  reference 
is  made  to  A.  Rockfordensis,  of  the  species  from  Nevada. 

Formation  and  locality. — Upper  horizon  of  the  Devonian  limestone,  on 
ridge  east  of  Yahoo  Canon,  Eureka  District,  Nevada. 
Cladopora  pulchra  Ronringer?    1876.     Greol.  Surv.  Michigan,  vol.  iii,  pt.  2,  p.  55. 

The  Eureka  specimens  although  occurring  in  the  upper  beds  of  the 
Devonian  are  closely  related  to  the  Upper  Helderberg  species,  C.  pulchra, 
and  appear  to  be  specifically  identical  with  it.  The  obtaining  of  more  and 
better-preserved  examples  may  prove  the  two  forms  to  be  specifically  dis- 
tinct, but  with  our  present  knowledge  a  separation  does  not  appear  to  be 
necessary. 

Formation  and  locality. — Upper  horizon  of  the  Devonian  limestone,  on 
ridge  east  of  Yahoo  Canon,  Eureka  District,  Nevada. 

Cladopora,  sp.  (und't). 

This  is  a  larger  branching  form  of  which  worn  sections  alone  have 
been  obtained.  It  occurs  in  the  central  or  lower  portion  of  the  Devonian 
formation  west  of  Spring  Valley. 

Numerous  fragments  of  an  imperfectly-preserved  species  of  Cladopora 
occur  in  the  silicious  Devonian  limestone;  the  stems  are  usually  about  5mm 
in  diameter  and  associated  with  a  species  of  Stromatopora  in  such  quanti- 
ties as  to  characterize  many  beds  where  other  fossils  are  wanting. 

Thecia  ramosa  Rominger?    1876.     Geol.  Surv.  Michigan,  vol.  iii,  pt.  2,  p.  69. 

This  rare  and  interesting  form  occurs  in  the  lower  portion  of  the  De- 
vonian, corresponding  to  its  position  in  the  Upper  Helderberg  limestones  at 
the  Falls  of  the  Ohio,  and  in  the  State  of  Michigan.  Dr.  Rominger 
describes  it  as  formed  of  "  stout,  branching,  sometimes  reticulated,  anasto- 
mosing stems,  from  half  an  inch  to  two  inches  in  diameter,  composed  of 
thick-walled,  conico-cylindrical  tubes  ascending  and  diverging  from  a  cen- 
tral imaginary  axis.  Orifices  unequal,  of  polygonal  form,  from  one  to  two 
millimeters  wide  at  the  edges  of  the  dilated  margins,  radiated  by  twelve 


FOSSILS  OF  THE  DEVONIAN. 


103 


prominent  spinulose  crests,  extending  through  the  whole  length  of  the 
channels.  Transverse  diaphragms  partly  simple  and  complete,  partly  in- 
complete, represented  by  lateral  squamiform,  horizontal  leaflets.  Pores 
large  and  very  numerous." 

The  species  is  represented  by  a  single  portion  of  a  stem  28mm  in  diam- 
eter; the  polygonal,  unequal  orifices  are  about  lmra  in  diameter  and  present 
the  character  given  them  by  the  author  of  the  species,  as  do  the  diaphragms 
and  large  pores.  Although  there  is  no  evidence  of  its  being  a  branching 
form,  as  there  is  but  a  portion  of  a  stem  in  the  collections,  it  seems  extremely 
probable  from  the  close  specific  characters  of  the  portion  we  have  that  it  is 
specifically  identical  with  the  Upper  Helderberg-  species. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
central  portion  of  Gray's  Canon,  Eureka  District,  Nevada. 

Syiingopora  Hisingeri  Billings.     1859.      Call.  Jour.,  11.  Ser.,  vol.  iv,  p.  116. 

In  New  York,  Canada,  Indiana,  etc.,  this  species  occurs  in  the  Upper 
Helderberg  limestones,  but  at  The  Gate,  northwest  of  Eureka,  it  is  associ- 
ated with  fossils  of  the  Chemung  horizon  in  the  Upper  Devonian  beds. 
Numerous  fine  specimens  were  found,  so  that  the  specific  identification 
hardly  admits  of  question. 

Syringopora  perelegans  Billings.     1859.      Can.  Jour.,  D.  Ser.,  vol.  iv,  p.  117. 

Specimens  referable  to  this  species  were  found  in  the  Lower  Devonian 
beds  at  Lone  Mountain,  and  also  at  the  summit  of  the  formation  at  The  Gate, 
northwest  of  Eureka,  showing  its  range  through  the  entire  Devonian  forma- 
tion. It  is  extensively  distributed  in  the  strata  of  the  hills  east  and  west 
of  Yahoo  Canon.  At  the  east  it  occurs  in  the  Upper  Helderberg  limestones. 

Aulopora  serpens  Goldfuss?    See  Geol.  Surv.  Michigan,  vol.  iii,  pt.  2.     1876. 

In  size,  manner  of  branching  and  reuniting  of  the  tubes,  this  species 
of  Aulopora  from  the  Lower  Devonian  beds  of  Gray's  Canon  corresponds 
to  the  descriptions  and  illustrations  given  of  the  American  form  identified 
with  that  species,  and  a  comparison  with  the  figures  given  by  Goldfuss 
indicates  that  this  identification  is  correct,  although  his  figures  show  a  some- 
what smaller  and  less  robust  form. 


104  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Cyathophyllum  corniculum  Milne-Edwards?     See  Geol.  Stirv.  Michigan,  vol.  iii,pt.  2,  p.  102. 

A  direct  comparison  with  examples  of  this  species  from  the  Upper 
Helderberg  limestones  at  the  Falls  of  the  Ohio  shows  very  little  difference 
between  them  and  a  similar  form  from  the  upper  beds  at  The  Gate,  north- 
west of  Eureka,  where  it  is  associated  with  Syringopora  Hisingeri,  another 
Upper  Helderberg1  species.  Until  more  perfect  specimens  are  obtained  a 
provisional  reference  is  made  as  above. 

CyathophyUum  rugosum  Edwards  and  Hairae.     See  Geol.    Surv.  Michigail,  VO'1.  iii,  pt.  2,  p. 
JOG.     1870. 

Well-marked  silicified  specimens  of  this  species  occur  in  association 
with  Cyathophyllum  Davidsoni  and  Diphyphyllum  Simcoense,  in  the  Lower 
Devonian  of  Lone  Mountain.  They  are  usually  more  or  less  subhemis- 
pherical  masses  with  occasional  cells  of  much  larger  size  than  distinguished 
the  Upper  Helderberg  examples  from  the  Falls  of  the  Ohio;  otherwise  no 
essential  differences  were  observed. 

Cyathophyllum  Davidsoni  Milne-Edwards.     See  Geol.  Surv.  Michigan,  vol.  iii,  pt.  2,  p.  107. 
1876. 

Occurs  with  the  preceding  species,  and  is  readily  identified  with  the 
forms  from  the  Hamilton  Group  of  Iowa.  It  appears  to  be  little  more  than 
a  small-celled  form  of  the  associated  C.  rugosum. 

Cyathophyllum,  n.  sp. 

A  compound  corallum  formed  of  corallites  that  increase  by  calicular 
and  interstitial  gemmation.  The  corallites  are  usually  circular,  and  vary 
from  3mm  to  25mm  in  diameter  in  the  same  specimen.  Frequently  several  will 
spring  from  the  calyx  of  an  old  corallite,  increase  rapidly  in  size,  forming 
a  subturbinate  form,  with  a  calyx  broad  and  expanded  about  the  margin, 
and  having  a  rather  deep  central  depression,  the  bottom  of  which  is  sometimes 
evenly  rounded,  and  again  with  a  small  central  protuberance  formed  by  the 
union  of  the  radiating  lamellae.  The  interstitial  corallites  start  from  the  sides 
of  the  older  ones  and  arise  alongside,  usually  remaining  at  the  same  rela- 
tive height  with  the  general  surface  of  the  corallum;  the  young  or  smaller 
corallites  vyanting  the  broad  margin  to  the  calyx,  the  deep  depression  occu- 
pying the  entire  area. 

The  lamellae  are  crenulated  on  the  margin  and  number  from  50  to  60 
in  the  circumference  of  the  calyx. 


FOSSILS  OF  THE  DEVONIAN. 

The  interlarnellar  spaces  are  divided  by  numerous  transverse  plates; 
the  central  transverse  diaphragms  are  very  small  if  present  at  all. 

This  is  a  very  distinct  and  handsome  species  allied  to  C.  ruyosum,  or 
what  that  species  would  be  if  growing  in  the  same  manner.  Still,  it  does 
not  appear  that  the  two  are  specifically  identical.  It  grows  in  quite  large 
masses,  as  a  fragment  shows  a  depth  of  15cm. 

Associated  with  the  preceding  species  at  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 

Cyathophyllum,  11.  sp. 

Single  conical  polyparia,  annulated  by  coarse  undulations  of  growth, 
and  longitudinally  striated  by  the  septal  furrows.  The  bases  of  root-like 
prolongations  from  the  outer  surface  often  obscure  these  features.  Calyx 
very  deep  and  opening  out  rapidly.  A  specimen  35mm  in  height  has  a  calyx 
22mm  in  depth,  with  a  diameter  of  26mm  at  the  margin.  Lamella?  from  f,0  to 
60  in  number.  This  is  a  strongly  marked  form,  unlike  any  other  known 
to  me. 

Associated  with  the  preceding  species. 
Acervuiaria  pentagona  Goldfuss.    See  Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  31.    1877. 

In  the  Paleontologic  report  of  the  Geological  Exploration  of  the  For- 
tieth Parallel,  Mr.  F.  B.  Meek  has  identified  this  species  from  the  Devonian 
limestones  of  the  White  Pine  Mountains,  and  given  an  illustration  of  the 
Nevada  specimens.  The  species,  as  it  occurs  in  the  Middle  Devonian,  at  the 
head  of  Brown's  Canon,  is  essentially  the  same  as  at  White  Pine,  and  there 
appears  to  be  no  question  of  its  identity  with  the  European  species. 

Pachyphyiium  Woodman!  (White)  II.  &  W.    1864.    Twenty-third  Ann.  Eep.  N.  Y.  State 
Cab.  Nat.  Hist,,  p.  231. 

This  is  a  strongly  marked  species,  and  a  comparison  of  specimens  from 
the  typical  locality  at  Rockford,  Iowa,  with  those  from  Nevada,  shows  no 
appreciable  differences  between  the  Chemung  form  and  the  Upper  Devonian 
specimens  occurring  on  the  ridge  west  of  Yahoo  Canon,  in  the  Eureka 
District, 
Diphyphyiium  Simcoense  Billings.  See  Geol.  Surv.  Michigan,  vol.  iii,  pt.  2,  p.  123.  1876. 

This  very  abundant  species  of  the  great  Corniferous  coral  reef  of  Can- 
ada, New  York,  Indiana,  etc.,  is  represented  by  a  number  of  specimens  from 
Lone  Mountain,  but  not  found  elsewhere.  The  stems  forming  the  colonies 


106  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

or  corallum  are  larger  than  the  average  in  the  species,  but  the  specific  iden- 
tity of  the  eastern  and  western  species  is  a  very  close  one. 

Cystiphyllum  Americanum  Milne-Edwards.     See  Geol.  Surv.   Michigan,   vol.  iii,  pt.   2,    p. 
138.     1876. 

As  there  is  considerable  variation  in  the  size  and  form  of  the  polyparia 
and  the  vesicles,  as  well  as  the  distinctness  of  the  plications,  in  the  forms 
referred  to  this  species,  it  is  quite  probable  that  the  one  under  consideration 
will  fall  within  its  limits.  It  presents  all  the  characters  common  to  many 
New  York  and  Ohio  specimens,  and  we  have  little  hesitancy  in  referring  it 
to  this  species. 

Formation  and  localities, — Lower  horizon  of  the  Devonian  limestone;  on 
the  divide  at  the  head  of  the  Reese  and  Berry  Canon,  and  at  Lone  Mountain, 
18  miles  northwest  of  Eureka,  Nevada. 

Cystiphyllum,  u.  sp. 

There  are  two  species  of  Cystiphyllum  in  the  collection  that  do  not 
appear  to  be  specifically  allied  to  any  described  forms.  One  has  the  outer 
surface  studded  with  little  nodes  and  the  calyx  of  considerable  depth,  with 
numerous  sharp  lamellae  that  in  some  instances  are  nearly  concealed  by 
coarse  vesicles.  The  corallum  is  about  40mm  in  length,  20mm  to  2nmm  in  diam- 
eter at  the  summit,  and  more  or  less  strongly  marked  by  broad  ridges  of 
growth.  The  other  species  has  the  latter  character  in  a  modified  degree, 
but  lacks  the  nodulose  surface ;  the  interior  of  the  calyx  is  filled  with 
vesicles  from  the  center  of  which  a  young  corallum  springs. 

At  Lone  Mountain  with  the  preceding  and  other  species. 

Besides  the  above-mentioned  forms,  there  are  two  species  of  Zaphrentis 
too  imperfect  for  description,  and  a  large  Cyathophylloid  coral  of  unknown 
specific  relations. 

BRACHIOPODA. 
Genus  LINGULA  Bruguiere. 

Lingula  Leeiia  Hall. 

Plate  xiii,  fig.  2. 
Lingula  leana  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  9,  pi.  ii,  fig.  12. 

The  Nevada  shell  is  not  quite  as  elongate  or  rounded  in  front  as  much 
.as  the  New  York  examples  of  this  species,  but  it  agrees  with  them  in  all 


FOSSILS  OF  THE  DEVONIAN. 


107 


-essential  particulars.  It  is  a  rare  species,  both  in  the  Hamilton  Group  of 
New  York  and  the  lower  horizon  of  the  Devonian  formation  at  Lone  Mount- 
ain, 18  miles  northwest  of  Eureka,  Nevada. 

Dimensions:  length,  17mm;  greatest  breadth,  12mm. 


Lingula  Ligea  Hall. 

Plate  ii,  fig.  2. 

Lingula  ligea  Hall,  1860.    Thirteenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  76. 
Ibid.,  1867.     Pal.  K  Y.,  vol.  iv,  p.  7,  pi.  i,  tig.  2 a,  &;  pi.  ii,  fig.  8. 

This  pretty  and  symmetrical  little  shell  is  represented  by  one  specimen 
that  in  external  appearance  is  identical  with  specimens  pf  L.  Ligea  now  before 
me,  from  the  Hamilton  Group  of  New  York. 

In  a  layer  of  limestone,  about  M)  feet  above  that  containing  the  above- 
mentioned  shell,  a  number  of  examples  of  a  form  that  may  be  only  a  varia- 
tion of  L.  Ligea  were  collected.  In  as  close  a  genus  as  Lingula,  however, 
this  variation  is  unusual,  and  a  varietal  distinction  is  made. 


Lingula  Ligea  var.  Nevadeiisis,  n.  var. 
Plate  ii,  fig.  3. 

Shell  below  the  average  size  of  L.  Ligea,  and  with  more  rounded  sides 
and  pointed  beaks  than  that  species. 

Surface  marked  by  fine  concentric  stria?  of  growth. 

The  interior  of  the  ventral  valve  shows  the  path  of  advance  of  two 
central  muscular  scars,  and  also  a  iateral  scar  on  each  side.  The  impres- 
sions of  the  scar  are  too  faint  to  be  of  any  service  in  determining  their 
character  or  number. 

Formation  and  locality  of  this  and  the  preceding  species,  Upper  Devo- 
nian of  Rescue  Hill,  Eureka  District,  Nevada. 

A  species  undistinguishable  from  this  occurs  in  the  Lower  Devonian  of 
the  south  slope  of  Sentinel  Mountain,  Eureka  District,  Nevada. 


108  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Lingula  Alba-pinensis,  n.  ep. 
Plate  ii,  figs.  1,  la. 

Shell  small,  elongate,  elliptical,  moderately  convex;  beaks  obtusely 
angular;  sides  of  shell  curving  with  a  gentle  convexity  from  the  lateral 
cardinal  slope  to  the  rather  abruptly  rounded  front 

Surface  marked  by  fine  concentric  striae  and  rather  strong  lines  of 
growth  for  so  small  a  species.  No  radiating  lines  have  been  observed. 

Dimensions:  length  of  the  largest  specimen  found,  6rai";  width  at  cen- 
ter, 3mm.  The  other  specimens  average  2.5mm  in  length  by  about  l..r,mm  in 
width. 

Associated  with  these  there  is  a  minute  form  that  differs  in  being  more 
broadly  elliptical;  otherwise  it  may  be  referred  to  L.  Alba-pinensis.  The 
latter  species  belongs  to  the  Devonian  Group  of  Lingula,  of  which  L.  Melie 
and  L.  Ligea  are  types,  and  is  also  very  much  like  the.  young  of  L  myti- 
loides  of  the  Carboniferous. 

In  the  Eureka  District  Lingula  Melie  (see  pi.  ii,  fig.  4)  is  the  only  Lin- 
gula yet  discovered  in  the  White  Pine  shale. 

Formation  and  locality. — Upper  Devonian,  White  Pine  shale,  White  Pine 
District,  Nevada, 

Lingula  Lonensis,  n.  sp. 
Plate  xiii,  figs.  1,  la. 

Shell  broadly  ovate ;  beaks  obtusely  angular,  the  sides  sloping  away  at 
an  angle  of  about  110°,  and  then  extending  forward  with  more  or  less  con- 
vexity to  the  broadly  rounded  front. 

Surface  marked  by  numerous  lines  of  growth  that  give  a  finely  imbri- 
cated appearance  to  the  outer  portions  of  the  shell.  No  radiating  lines  or 
striae  are  visible  on  the  specimens  before  us.  Two  specimens  measure: 
length,  10mm;  width,  8mm;  length,  llmm;  width,  10mm,  respectively. 

The  specimens  are  imbedded  in  a  shaly  limestone,  and  are  very  much 
compressed,  which  gives  them  a  broader  outline  than  when  in  a  natural 
condition. 

The  species  is  allied  to  Lingula  Lucretia  Billings  (Pal.  Foss.,  vol.  ii,  pt. 


FOSSILS  OF  T11E  DEVONIAN. 


109 


1,  p.  13,  fig.  3.     1874),  from  the  Gasp^  limestone,  but  differs  in  surface  char- 
acters. 

Formation  and  locality. — In  the  lower  horizon  of  the  Devonian  limestone 
of  Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


Lingula  White!,  n.  sp. 
Plate  xiii,  fig.  3. 

Shell  above  the  average  size,  subelliptical  in  outline,  the  length  and 
breadth  as  5  to  3;  the  cardinal  slopes  of  the  dorsal  valve  converge  at  an 
angle  of  20°;  front  broadly  rounded  and  sides  subparallel,  curving  slightly 
outward.  The  dorsal  valve  is  quite  convex  and  a  little  flattened  along  the 
center  towards  the  front. 

Surface  marked  by  fine  concentric  and  radiating  striae,  and  when 
the  outer  shell  is  partially  decorticated  strong  radiating  lines,  crossed  by 
raised  concentric  striae,  give  a  somewhat  reticulated  appearance  to  the  sur- 
face. The  length  of  the  specimen  described  is  29mm  and  the  breadth  1 7mm. 

The  general  outline  of  the  species  is  similar  to  that  of  Lingula  squami- 
formis  Phillips  (Mon.  Brit.  Foss.  Brach.  Davidson,  vol.  ii,  p.  i05,  pi.  xlix, 
figs.  1— 10),  of  the  Carboniferous  rocks,  but  the  valves  are  more  convex 
and  the  scars  on  the  interior  of  the  dorsal  valve  differently  arranged.  I 
know  of  no  closely  related  Devonian  species. 

A  cast  of  the  interior  of  the  dorsal  valve  was  obtained  from  a  fragment 
of  limestone  in  which  the  shell  adhered  to  the  matrix  by  its  exterior  sur- 
face and  left  the  imprint  of  the  vascular  markings  and  muscular  scars 
beautifully  and  distinctly  defined  on  the  cast.  It  is  of  great  interest,  as  it 
affords  the  opportunity  for  the  comparison  of  the  structure  with  that  of  living 
forms  of  the  genus,  and  shows  that  the  strong  generic  resemblance  of  the 
outer  surface  of  the  shell  to  that  of  recent  species  is  also  present  in  the 
more  important  muscular  scars  on  the  interior  surface. 

At  the  posterior  end,  just  within  the  apex  of  the  valve,  the  cast  of  the 
elongate  divaricator  muscular  scar  (d,  plate  xiii,  fig.  3)  is  well  impressed: 
it  is  transverse  and  arches  forward  a  little  at  the  sides,  back  of  the  initial 
points  of  the  path  of  the  advance  of  the  posterior  adductor  and  adjuster 


110  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

muscular  scars.  The  posterior  adductor  scars  (pa)  are  large,  elongate-oval 
in  outline,  and  so  situated  that  their  anterior  portions  cross  a  line  drawn 
through  the  transverse  center  of  the  valve,  while  the  posterior  ends  point 
back  to  their  path  of  advance;  they  are  separated  by  the  track  of  advance 
of  the  anterior  adductor  scars  (aa),  which  are  seen  just  in  advance  of 
them  as  very  small,  slightly  impressed  oval  spaces.  The  area  of  the  ad- 
justor  muscular  scars  (ad)  and  their  path  of  advance  is,  as  a  whole,  more 
or  less  triangular,  and  situated  one  on  each  postero-lateral  portion  of  the 
valve.  The  front  margin  of  the  area  is  rather  broad  and  divided  into  four 
small,  somewhat  indistinct  lobes;  posteriorly  the  area  contracts  to  the  in- 
itial point  of  the  path  of  advance;  two  scars  appear  to  be  defined  on  the 
anterior  two-thirds  of  each  area;  they  are  elongate  and  include  two  of  the 
little  lobes  of  the  anterior  margin  within  the  area  of  each,  and  appear  to 
represent  the  point  of  attachment  of  the  exterior  and  posterior  adjuster 
muscles;  there  is  a  small  space  divided  off  by  raised  lines  that  may  be  the 
central  adjustor  scar,  but  it  is  not  clearly  denned. 

Between  the  areas  of  the  adjustor  scars  and  the  large  central  area  of 
the  adductors  there  is  a  sharp,  narrow  ridge  that  distinctly  separates  them. 
A  narrow  elongate  area  (pp),  outside  of  the  area  of  the  adjustor  scars,  was 
probably  the  point  of  attachment  of  the  posterior  parietal  muscle,  and  the 
lateral  and  outer  walls  of  the  perivisceral  cavity  seem  to  have  left  evidence 
of  their  presence  on  the  margins  (w}  of  the  central  area. 

The  great  pallial  sinuses  approximate  quite  closely  towards  the  front, 
curving  gently  outward  and  backward  around  the  central  area  to  opposite 
the  anterior  margin  of  the  area  of  the  adjustor  muscular  scars,  around 
which  they  curve  to  the  narrow  margin  just  within  the  exterior  border  of 
the  shell;  their  further  course  cannot  be  traced,  but,  from  the  narrow  area 
between  the  posterior  parietal  area  and  the  margin,  the  sinuses  must  have 
been  very  narrow,  and  with  very  minute,  if  any,  lateral  or  internal  ramus- 
cules.  The  anterior  lateral  ramifications  of  the  sinuses  are  strongly  defined 
as  they  spring  from  the  main  sinus,  becoming  smaller  and  bifurcating  or 
branching  towards  the  margin  of  the  valve;  no  inner  ramifications  are  to 
be  seen  on  the  space  (i)  between  the  great  sinus  and  the  perivisceral  area 
on  the  dorsal  valve,  a  feature,  however,  that  is  well  shown  on  a  fragment 


FOSSILS  OF  THE  DEVONIAN. 


Ill 


of  a  ventral  valve,  where  this  area  and  the  space  occupied  by  the  anterior 
adductor  scars  in  the  dorsal  valve  is  occupied  by  the  short,  strong  ramuscules 
from  the  great  sinuses.  Over  the  central  portion  of  the  cast  the  radiating 
lines  of  the  inner  surface  of  the  shell  are  seen  crossing  the  muscular  scars 
and  vascular  markings,  and  somewhat  complicate  the  study  of  the  latter. 
The  draughtsman  has  represented  these,  as  also  all  the  details,  with  accuracy. 

On  comparing  this  with  the  interior  of  the  corresponding  valve  of 
Ling  da  Elder  i,  of  the  Trenton  limestone  of  Wisconsin,  described  by  Prof, 
R  P.  Whitfield,8  we  observe  in  the  latter  the  strong  extension  of  the  great 
pallial  sinuses  nearly  around  the  posterior  end  of  the  perivisceral  cavity 
and  back  of  the  divaricator  scar;  the  greater  anterior  expansion  of  the  pal- 
lial sinuses,  and  the  smaller  area  of  the  adjuster  muscular  scars.  The 
former  character  is  unknown  in  L.  Whitei,  but  is  present  in  the  recent  spe- 
cies so  beautifully  illustrated  by  Hancock.9 

The  two  paleozoic  species  possess,  however,  the  large  posterior  ad- 
ductor scars,  the  postero-lateral  adjuster  scars,  and  the  absence  of  the  inner 
ramuscules  of  the  posterior  extension  of  the  pallial  sinuses,  features  that 
distinguish  them  from  Lingula  anatina  and  other  living  species. 

The  character  of  the  anterior  ramifications  of  the  great  sinuses  of  L. 
Whitei  resembles  that  of  L.  affinis  more  closely  than  that  of  any  other 
species. 

To  afford  the  means  of  a  direct  comparison  between  the  Silurian,  De- 
vonian, and  a  recent  Lingula,  an  outline  figure  of  the  interior  of  the  dorsal 
valve  of  a  species  from  each  horizon  is  given  on  plate  xxi,  figs.  18,  19,  and 
20,  in  which  the  muscular  scars  and  vascular  markings  of  each  are  shown. 

The  specific  name  of  the  Devonian  species  is  given  in  honor  of  Dr.  C. 
A.  White,  geologist  and  paleontologist. 

Formation  and  locality. — Lower  portion  of  the  Devonian  limestone, 
southwest  spur  of  Atrypa  Peak,  Eureka  District,  Nevada. 

8Aruer.  Jour.  Sci.,  lid  ser.,  vol.  xix,  p.  472,  1880. 

9  Organization  of  the  Braclripoda,  by  Albany  Hancock,  esq.,  1858.    Trans.  Royal  Phil.  Soc.,  pis.  64-66. 


112  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  DISCINA  Lamarck. 

Discina  toiuuta  Hall. 
Plate  xiii,  fig  5. 

Orbicula  minuta  Hall,  1843.    Geol.  Rep.  Fourth  District  of  New  York,  p.  180. 
Discina  minuta  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  16,  pi.  i,  fig.  Wa-b. 

This  small  and  pretty  species  is  represented  by  a  number  of  examples 
that  correspond  closely  with  the  typical  specimens  from  the  Marcellus  shale 
of  New  York,  and  which  are  considered  identical  with  them,  although 
separated  by  a  distance  of  1,800  miles,  and  occurring  at  a  different  horizon 
in  the  Devonian  Group. 

The  New  York  specimens  vary  from  1.5mm  to  4mm  in  diameter,  while 
the  largest  from  Nevada  is  4mm  in  its  greater  diameter,  and  of  about  the 
same  convexity  as  examples  of  the  same  size  from  New  York. 

Formation  and  locality. — Upper  horizon  of  the  Devonian  limestone,  at 
The  G^te,  northeast  of  Eureka,  Nevada. 

Discina,  sp.  (T) 

Considerable  interest  is  attached  to  this  shell,  as  it  is  very  rare  and 
the  only  species  of  the  genus  from  the  Lower  Devonian  of  the  Rocky 
Mountain  area,  but  one  imperfect  specimen  showing  the  two  valves  united 
occurs  in  the  collections.  In  general  form  it  is  not  unlike  Discina  media  of 
the  Hamilton  Group  of  New  York. 

Formation  and  locality. — Lower  Devonian  of  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 

Discina  Lodensis  Hall. 
Plate  ii,  figs.  5,  5  a. 

Orbicula  lodensis  Hall,  1843.     Geol.  Rep.  Fourth  Dist.  N.  Y.,  p.  223. 

lodensis  Vanuxem,  1842.  *Geol.  Rep.  Third  Dist.  N.  Y.,  p.  168.     (Wood  cut 

used  in  advance  of  publication  of  the  Report  on  the  Fourth  District*) 
Discina  lodensis  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  22,  pi.  i,  figs  14  a-f;  pi.  ii,  fig.  35. 
lodensis  Rathbun,  1874.    Bull.  Buflalo  Soc.  Nat,  Sci.,  vol.  ii,  p.  257.    Ibid.,  1878 

Proc.  Boston  Soc.  Nat.  Hist.,  vol.  xx,  p.  17. 
Compare  D.  media  Hall,  1857.    Pal.  N.  Y.,  vol.  iv,  p.  20,  pi.  ii,  figs.  25-28. 


FOSSILS  OF  THE  DEVONIAN. 


113 


On  a  direct  comparison  with  authentic  specimens  of  this  species  from 
the  Genesee  slate  of  New  York,  no  differences  appear  that  are  of  specific 
value. 

Professor  Hall  says,  in  comparing  D.  media  of  the  Hamilton  Group  of 
New  York  with  D.  Lodensis,  that  the  former  may  possibly  be  only  a  well- 
marked  variety  of  D.  Lodensis  (ibid.,  p.  21).  In  this  I  would  fully  concur. 
In  studying  a  good  series  of  Discina  nitida,  as  illustrated  by  Davidson,  con- 
siderable range  of  variation  in  convexity,  outline,  and  the  position  of  the 
apex  is  apparent,  and  no  doubt  other  species  are  subject  to  as  great  varia- 
tions, arising,  as  they  may,  from  the  nature  of  the  local  environment  during 
the  life  of  the  animal;  the  character  of  the  sediments  and  conditions  of 
fossilization. 

Mr.  Rathbun  identifies  this  species  from  the  Devonian  of  Brazil,  S.  A. 

Formation  and  locality. — Upper  Devonian.  White  Pine  shale  on  the 
east  side  of  Applegate  Canon,  White  Pine  Mining  District,  Nevada. 


PHOLIDOPS  Hall. 

Pholidops  bellula,  n.  sp. 
Plate  ii,  figs.  6,  6 a,  &. 

Shell  minute,  broadly  oval,  depressed;  apex  eccentric,  situated  about 
one-third  the  distance  between  the  anterior  and  posterior  margins. 

Surface  marked  by  a  few  fine  concentric  striae. 

The  interior  of  the  dorsal  valve  presents  a  rather  wide,  unbroken  mar- 
gin surrounding  the  rounded  concave  interior.  Near  the  center  of  the  shell 
two  oval,  slightly-oblique  elevated  scars  occur.  No  other  scars  are  discern- 
ible. In  the  cast  Ihe  bilobed  scars  are  shown  as  a  rather  deep  impression, 
the  apex  of  the  shell  bein<r  entirely  truncated.  Substance  of  the  shell  cal- 
careous. Average  size,  2.5mm  by  2mm.  No  ventral  valves  were  discovered. 

In  general  form  this  species  resembles  Pholidops  ovalis  Hall,  (Twenty- 
eighth  Ann.  Rep.  N.  Y.  State  Mus.  Nat.  Hist.,  p,  149,  pi.  xxi,  figs.  1,  2)  of 
the  Niagara  Group,  and  P.  Hamiltonue  Hall  (Pal.  N.  Y.,  vol.  iv,  p.  32,  pi.  iii, 
figs.  6-9,  1867)  of  the  Hamilton  Group  of  New  York.  It  differs  from  each, 
and  is  specifically  distinct  from  any  form  with  which  we  are  acquainted. 
8  c  D  w 


1 14:  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

Formation  and  locality. — Lower.  Devonian  of  Brush  Peak,  Eureka  Dis- 
trict, and  at  the  same  horizon  at  Lone  Mountain,  18  miles  northwest  of 
Eureka,  Nevada. 

Fholidops  quadrangularis.  n.  sp. 
Plate  ii,  fig.  7. 

Shell  broadly  oval,  or  subquadrangular ;  moderately  elevated.  Sides 
nearly  straight,  which  gives  the  quadrangular  outline  to  the  shell.  Apex 
eccentric  and  a  little  elongate.  Slope  from  the  apex  to  the  margin  uniform. 
Surface  marked  by  irregular,  not  very  prominent  lamellose  striae.  Substance 
of  shell  calcareous.  Dimensions:  Breadth,  f».5mm;  length,  about  6.5mm. 

This  species  is  unlike  any  described  form  known  to  us,  and  although 
only  represented  by  a  single  valve  showing  the  exterior,  it  is  too  well  marked 
to  be  confused  with  any  species  from  the  Eastern  United  States. 

Formation  and  locality. — Lower  Devonian  at  Lone  Mountain,  1 8  miles 
northwest  of  Eureka,  Nevada. 

Genus  ORTHIS  Dalman 

Orthis  McFarlanei  Meek. 

Orthis  Me. Farlanei  Meek,  1868.   Trans.  Chicago  Acad.  Sci.,  vol.  i,  p. 88,  pi.  xii,  figs.  1  a-h. 

This  large  species  is  so  strongly  marked  by  its  peculiar  form  that  the 
identification  is  rendered  very  satisfactory,  although  based  on  imperfect 
specimens.  Its  short  hinge  line,  great  convexity  of  the  dorsal  valve,  and 
narrow  umbonal  region  give  it  the  appearance  of  Pentamerus  galeatus,  as 
mentioned  by  Meek.  The  Nevada  specimens  show  the  fine  radiating-  striae 
and  minutely  punctate  surface  with  great  distinctness,  as  in  the  original  types 
of  the  species  from  the  Mackenzie  River  Basin,  British  America.  Mr.  Meek 
states  that  he  had  seen  specimens  which  he  believed  to  be  identical  with 
this  species  from  the  Devonian  of  Iowa  and  Illinois. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone,  west 
slope  of  County  Peak,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


115 


Orthis  impressa  Hall. 
Plate  xiii,  fig.  13. 

Orthis  impressa  Hall,  1843.    Geol.  Eep.  Fourth  District  of  New  York,  p.  268  and  p.  267, 

fig.  2. 

impressa  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  60,  pi.  viii,  figs.  11-19. 
impressa  Whitfield,  1883.     Geol.  of  Wisconsin,  vol.  iv,  p.  326,  pi.  xxv,  figs.  13^15. 
Compare  0.  Tulliensis  Vauuxem,  1842,     Geol.  Rep.  Third  District,  New  York,  p.  55. 

0.  loicensis  Hall.  1858,  Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  488,  pi.  ii,  figs. 
4  a-i,  and  0.  Me.  Farlanei,  Meek,  loc.  cit.,  p.  114. 

In  New  York  this  species  is  found  in  the  Chemung  Group,  and  is  re- 
garded by  Professor  Hall  as  closely  allied  to  Orthis  Tulliensis,  of  the  Tully 
limestone,  which  occurs  about  1,000  feet  lower  in  the  strata,  no  species  of 
Orthis  being  known  in  the  interval.  In  Nevada  the  relative  position  of  the 
two  forms  is  somewhat  reversed;  0.  impressa  is  found  only  at  the  base  of 
the  Devonian,  and  0.  Tulliensis  at  the  base  arid  near  the  summit,  4,000  feet 
above. 

A  comparison  of  the  Chemung  specimens  from  New  York  wfth  the 
Nevada  examples  shows  a  most  perfect  identity  between  them,  while  the 
0.  Tulliensis  is  quite  as  decided  in  its  characters  as  in  New  York.  Associated 
with  0.  impressa,  at  Lone  Mountain,  there  is  a- more  convex  form  that  is  of 
the  type  of  0.  Tulliensis,  and  it  may  be  referred  to  it. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak;  2  miles  east  of  Castle  Mountain;  west  slope  of  County 
Peak,  and  Lone  Mountain,  18  miles  northwest  of  Eureka,  Eureka  District, 
Nevada. 


Orthis  Tulliensis  Vauuxem. 
JPlateii,  figs.  12,  12  a. 

Orthis  tulliensis  Vanuxem,  1842.     Geol.  Rep.  Third  District  New  York,  p.  164  and  fig. 

2,  on  p.  163. 

tulliensis  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  55,  pi.  vii,  figs.  5cu-k. 
Compare  0.  loicensis  Hall,  1858.    Geol.  Eep.  Iowa,  vol.  i,  pt.  2,  p.  488,  pi.  ii,  figs.  4 a-/. 

The  facts  connected  with  the  distribution  and  range  of  this  species  have 
been  mentioned  in  the  notes  of  the  preceding  species.  The  specimens  from 
The  Gate,  northwest  of  Eureka,  are  not  quite  as  gibbose  as  the  majority 


116  PALEONTOLOGY  OF  THE  EUEEKA  DISTKICT. 

of  the  New  York  examples,  but  their  specific  identity  is  unquestionable. 
The  specimens  from  the  lower  horizon  at  Lone  Mountain  are  preserved  in  a 
different  matrix  and  the  outer  surface  is  mostly  exfoliated,  which  gives 
them  a  dissimilar  appearance,  but  no  specific  variation  can  be  determined 
between  them  and  those  from  the  upper  horizon  at  The  Gate. 

formation  and  localities. — Devonian  limestone,  higher  beds  at  The  Gate, 
northwest  of  Eureka,  and  lower  beds  at  Lone  Mountain,  18  miles  northwest 
of  Eureka,  Nevada. 

Genus  SKENIDIUM  Hall. 

Skenidium  Devonicum,  u.  sp. 
Plate  xiii,  lig.s.  4,  4n. 

Shell  small,  subpyramidal ;  hinge  line  a  trifle  shorter  than  the  greatest 
width  of  the  shell;  a  sharp,  median  fold  marks  the  ventral  valve  and  a 
.slight  sinus  the  dorsal.  Ventral  valve  elevated,  beak  slightly  incurved  over 
a  high  area  that  is  divided  midway  by  a  large  deltoidal  foramen.  Dorsal 
valve  nearly  flat;  area  very  short;  foramen  short  and  broad;  cardinal  pro- 
cess extends  as  a  median  septum  towards  the  lower  portion  of  the  valve. 

Surface  marked  by  strong  radiating  striae  that  increase  by  implanta- 
tion. 

Dimensions:  length,  3.5mm;  breadth,  4.. r)mni;  elevation  of  ventral  valve, 
1 .5mra. 

This  species  has  a  less  elevated  area,  finer  and  sharper  striae  than  Ske- 
itidiHiH  insignis-=z(Ortliis  insiynis  Hall,  Pal.  N.  Y.,  vol.  iii,  p.  173,  pi.  xiii,  figs. 
1, ">-!;"),  1859)  of  the  Lower  Helderberg  limestone  of  New  York;  otherwise 
the  two  strongly  resemble  each  other. 

This  is  the  first  time  that  the  genus  Skenidium  has  been  reported  as 
occurring  in  Devonian  strata,  the  species  previously  referred  to  it  coming 
from  the  Lower  and  Upper  Silurian  formations. 

Formation  and  locality. — Devonian  limestone,  lower  horizon,  Lone 
Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


117 


Genus  STKEPTOJRHYNCHUS  King. 

Streptorhynchus  Chemungensis  Conrad  (Sp.). 
Plate  xiii,  figs.  7,  16. 

Strophomena  Chemungensis  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p. 

257. 

Ufurcata  Hall,  1842.     Geol.  Eep.  Fourth  District  New  York,  p.  266,  fig.  2. 
arctostriata  Hall,  1842.     Ibid.,  p.  266,  fig.  3. 
pectinacea  Hall,  1842.     Ibid.,  p.  266,  fig.  4. 
Orthis  perversa  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  137. 

inequalis  and  0.  pravus  Hall,  1858.    Geol.  Iowa,  vol.  i,  pt.  2,  p.  490. 
Streptorhynchus  Pandora  Billings,  1860.     Canadian  Jour.,  vol.  v,  p.  266,  and  Geology 

of  Canada,  1863,  p.  369,  fig.  384. 
Orthisina  arctostriata  Hall,  1860.  Thirteenth  Ann.  Kep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  80. 

alternata  Hall,  1860.    Ibid.,  p.  81. 

Streptorhynchus  Chemungensis  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  67,  plates  iv,  ix,  x. 
var.  A.  Streptorhynchus  pandora  Billings, 
var.  B.  8.  arctostriata  Hall, 
var.  C.  8.  perversa  Hall. 

var.  D.  8.  pectinacea  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  pp.  68-73. 
Pandora  Nicholson,  1874.    Pal.  Prov.  Ontario,  p.  70. 

Hemipronites  Chemungensis,  var.  arctostriata  Meek,  1877.     Geol.  Expl.  Fortieth  Par., 
vol.  iv,  p.  35,  pi.  iii,  fig.  2. 

Three  "quite  distinctly  marked  varieties  of  this  extremely  variable  spe- 
cies were  collected  from  the  Devonian  limestone  of  Lone  Mountain  and  the 
Eureka  District. 

The  first  is  that  of  the  typical  form  of  shell  described  by  Conrad, 
many  illustrations  of  which  are  given  by  Professor  Hall  in  volume  four  of 
the  Paleontology  of  New  York  (plate  x,  figs.  11-17).  The  Nevada  form  is 
shown  on  our  plate  xiii,  fig.  16.  Another,  and  by  far  the  most  abundantly 
represented  variety,  is  var.  Pandora  (Pal.  N.  Y.,  vol.  iv,  pi.  iv,  figs.  11-19; 
pi.  ix,  figs.  18-25,  27;  and  pi.  x,  fig.  1). 

In  New  York  the  species  ranges  from  the  Upper  Helderberg  up  into  the 
Chemung  Group,  and  in  the  Eureka  District  from  the  base  to  the  summit  of 
the  Devonian  limestone.  At  The  Gate,  northwest  of  Eureka,  the  small 
form  characteristic  of  the  Chemung  Group  of  New  York,  also  of  the  Cor- 
niferous  limestone  of  the  Upper  Helderberg,  occurs  in  a  dark  limestone. 
This  is  the  exact  locality  from  which  the  specimen  mentioned  by  Mr.  Meek 
was  obtained  and  referred  by  him  to  the  variety  arctostriata.  The  speci- 


118  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

men  as  figured  by  Mr.  Meek  is  like  those  before  me,  one  of  which  (plate 
xiii,  fig.  7)  varies  slightly  from  his  figure  and  those  illustrated  by  Professor 
Hall  (Pal.  N.  Y.,  vol.  iv,  pi.  x,  figs.  1,  2.) 

The  other  variety  represented  in  Nevada,  var.  perversa,  is  limited  to 
the  Lower  Devonian  horizon,  although  found  at  somewhat  widely  separated 
localities.  In  New  York,  it  is  found  both  in  the  Upper  Helderberg  and 
Hamilton  Groups. 

Formation  and  localities. — Devonian  limestone,  Lone  Mountain,  1 8  miles 

/ 

northwest  of  Eureka,  and  several  localities  within  the  Eureka  District, 
Nevada;  also  on  north  end  of  the  Pinon  Range,  Nevada. 

Genus  STROPHOMENA  Blainville. 

Strophomena  rhomboidalis  Wilckens  (Sp.). 

For  synonyms,  see  Davidson's  Monograph  of  the  British  Silurian  Brachiopoda,  vol.  iii, 
p.  281;  and  Pal.  X.  Y.,  vol.  iv,  p.  76. 

This  widely-distributed  species  was  found  in  but  one  locality  on  Lone 
Mountain,  not  being  recognized  within  the  limits  of  the  map  of  the  Eureka 
District.  The  specimens  are  of  the  ordinary  character,  with  rather  strong 
concentric  undulations.  They  are  associated  with  Strophodonta  perplana, 
S.  ampla,  and  Streptorhynchus  Chemungensis,  var.  Pandora. 

The  species  has  been  recognized  in  the  Lower  Carboniferous  of  Utah, 
and  at  the  same  horizon  in  the  Spring  Mountain  Range  of  Nevada,  but  not 
before  in  the  Devonian  of  the  Rocky  Mountain. 

Formation  and  localities. — Lower  Devonian  horizon  of  Lone  Mountain, 
18  miles  northwest  of  Eureka,  Nevada;  also  in  the  Lower  Devonian,  on  the 
north  end  of  the  Pinon  Range,  Nevada. 

Genus  STROPHODONTA  Hall. 

Strophodonta  demissa  Conrad  (Sp.). 
Plate  ii,  figs.  9,  9  a,  ft. 

Strophomena  demissa  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p.  258, 

pi.  xiv,  fig.  14. 
Strophodonta  dimosa  (?)  Owen,  1862.    Geol.  Surv.  Wis.,  Iowa,  and  Minn.,  tab.  iii,  A, 

fig.  14. 


FOSSILS  OF  THE  DEVONIAN. 


119 


Strcphomena  (Strophodonta)  demissa  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat. 

Hist,,  p.  137. 

Strophodonta  demissa  Hall,  1858.    Geol.  Iowa,  vol.  i,  pt.  2,  p.  495,  pi.  iii,  fig.  5. 
Strophomena  demissa  Billings,  18C1.     Canadian  Jour.,  vol.  vi,  p.  341,  figs.  116-118. 

demissa  Billings,  1863.    Geology  of  Canada,  p.  367,  figs.  377 a-d. 
Strophodonta  demissa  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  pp.  81, 101,  and  114,  pis.  xi,  xii, 

xvii,  xix. 
Sti'ophomena  (Strophodonta)  demissa  Meek,  1868.    Trans.  Chicago  Acad.  Sci.,  vol.  i,  p.  87, 

figs.  Qc-c. 
Strophodonta  demissa  Nicholson,  1873.    Pal.  Prov.  Ontario,  p.  65. 

demissa  Whitfield,  1883.    Geol.  of  Wisconsin,  vol.  iv, p.  327,  pi.  xxv,  fig.  18. 

This  species  in  New  York  occurs  throughout  the  Devonian.  It  has 
also  been  found  in  Illinois,  Iowa,  and  to  the  far  Northwest,  in  the  Mackenzie 
River  Basin  In  the  Eureka  District  it  is  restricted,  as  far  as  known,  to 
the  Lower  Devonian  horizon.  The  specimens  are  below  the  average  size 
of  those  from  the  Hamilton  Group  of  New  York,  corresponding  in  this 
respect  to  the  Upper  Helderberg  form;  they  are  also  more  finely  striated. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
midway  of  Gray's  Canon,  Eureka  District,  and  at  Lone  Mountain,  18 
miles  northwest  of  Eureka,  Nevada. 


Strophomena  (Strophodonta)  patersoni  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State  Cab. 

Nat,  Hist.,  p.  114. 

Strophomena  Patersoni  9  Billings,  1861.    Can.  Jour.,  vol.  vi,  p.  340,  fig.  115. 
Strophodonta  patersoni  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  89,  pis.  xii,  xiii. 
Strophomena  Patersoni  Nicholson,  1873.    Pal.  Prov.  Ontario,  p.  67. 

There  is  but  one  specimen  of  the  ventral  valve  of  this  species  in  the 
collection,  but  its  depressed  convex  form,  arching  wrinkles  between  the 
coarser  stria?,  and  the  fine  intermediate  radiating  striae  give  it  all  the  promi- 
nent characters  of  the  species.  In  New  York  and  Canada,  S.  Patersoni  is 
an  Upper  Helderberg  species,  not  being  known  in  the  Hamilton  or  Chemung 
Groups.  Its  horizon  in  New  York  and  Canada  is  the  equivalent  .of  the 
Lower  Devonian  horizon  in  the  Eureka  District. 

Formation  and  locality. — Devonian  formation,  lower  horizon,  Lone 
Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


120  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

Strophodonta  inequiradiata  Hall. 
Plate  11,  figs.  11,  11  a. 

Strophomena  (Strophodonta)  inequiradiata  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State 

Cab.  Nat.  Hist.,  p.  113. 
incequistriata  Billings,  1861.    Can.  Jour.,  vol.  vi,  p.  338,  fig.  113.    Ibid., 

Geology  of  Canada,  1863,  p.  367,  fig.  375. 

Strophodonta  inequiradiata  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  87,  pis.  xi,  xii,  xiii. 
Strophomena  inequiradiata  Billings,  1874.     Pal.  Foss.,  vol.  ii,  pt.  1,  p.  24. 

This  species  is  closely  allied  to  S.  Patersoni,  as  is  shown  by  a  series  of 
specimens  from  the  Upper  Helderberg  Group  of  New  York.  The  Nevada 
specimens,  however,  represent  the  well-marked  characters  of  each  species, 
so  that  there  is  little  danger  of  mistaking  one  for  the  other.  They  occur 
at  the  same  stratigraphic  horizon,  but  in  localities  15  miles  distant  from 
each  other. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Eureka  District,  Nevada. 

Strophodonta  perplana  Conrad  (Sp.). 

Plate  xiii,  fig.  11. 

Strophomena  perplana  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p.  257r 
pi.  xiv,  fig.  11. 

pluristriata  Conrad,  idem.,  p.  259. 

delthyris  Conrad,  idem.,  p.  258. 

crenistria  Hall,  1843.    Rep.  Fourth  Geol.  District  New  York,  p.  171. 

nervosa  Hall,  idem.,  p.  266,  fig.  1. 
Strophodonta  fragilis  Hall,  1857.     Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist,  p.  143. 

fragilis  Hall,  1858.    Geol.  Eep.  Iowa,  vol.  i,  pt.  2,  p.  496,  pi.  iii,  figs.  6  a-c. 
Strophomena  perplana  Billings,  1861.     Can.  Jour.,  vol.  vi,  p.  343. 
Strophodonta  perplana  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  pp.  92,  98,  and  113,  pis.  xi,  xiiir 

xvii,  and  xix. 
Strophomena  perplana  Nicholson,  1873.    Pal.  Prov.  Ontario,  p.  64. 

This  well-marked  species  ranges  from  the  lower  horizon  to  nearly  the 
summit  of  the  Devonian  limestone.  It  is  represented  by  a  number  of  speci- 
mens which,  although  somewhat  imperfect,  exhibit  the  general  outline,  slight 
convexity,  and  fine  surface  striae  of  the  ventral  valve,  as  also  the  large  flabel- 
liforni  divaricator  muscular  impressions.  In  New  York  it  is  found  to  pass 


FOSSILS  OF  THE  DEVONIAN.  121 

from  the  Upper  Helderberg  through  the  Hamilton  and  into  the  Chemung 
Group.  Its  geographic  range  also  includes  the  Province  of  Ontario,  Can- 
ada, and  the  States  of  Illinois  and  Iowa. 

Formation  and  localities. — Devonian  limestone,  Comb's  Peak  and  Newark 
Mountain,  Eureka  District;  Lone  Mountain,  18  miles  northwest  of  Eureka,. 
Nevada. 

Strophodonta  punctulifera  Conrad  (sp.) 
Plate  xiii,  fig.  10. 

For  list  of  synonyms  and  remarks,  see  Paleontology  of  New  York,  vol.  iii,  p.  188; 
vol.  iv,  p.  95 ;  Pal.  Province  of  Ontario,  p.  68. 

This  species  has  usually  been  considered  a  Lower  Helderberg  form, 
although,  as  stated  by  Professor  Hall,  Mr.  Billings,  and  Professor  Nicholson, 
it  is  closely  allied  to,  if  not  identical  with  S.  ampla,  of  the  Upper  Helder- 
berg and  Hamilton  Groups.  The  Nevada  specimens  show  a  convex  dorsal 
valve,  slightly  concave  about  the  umbo,  with  strong  radiating  striae  and: 
punctate  surface,  the  latter  showing  where  the  surface  is  covered  with  fine 
concentric  striae.  The  Nevada  shell  is  not  referable  to  S.  ampla,  as  found 
in  New  York,  and  as  it  approaches  S.  punctulifera  very  closely  the  reference 
is  made  to  that  species.  . 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone,. 
Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

Strophodonta  arcuata  Hall  ? 

Strophodonta  arcuata  Hall,  1858.    Geol.  of  Iowa,  vol.  i,  pt.  2,  p.  492,  pi.  iii,  figs.  Ia-c 

2  a,  6,  e,  f. 
Calvin,  1878.    Bull.  U.  S.  Geol.  Survey,  vol.  iv,  p.  728. 

A  comparison  with  specimens  from  Rockford,  Iowa  shows  the  Nevada 
shell  to  be  less  convex  than  the  average  examples,  but  not  less  so  than  some. 
It  agrees  otherwise  in  nearly  every  particular. 

Formation  and  locality. — Devonian  limestone,  south  spur  of  Atrypa  Peak,, 
Eureka  District,  Nevada. 


122  PALEONTOLOGY  OF  THE  EUEEKA  D1STKICT. 

Strophodonta  Calvini  Miller. 
Plate  xiii,  fig.  6. 

Strophodonta  quadrata  Calvin,  1878.    Bull.  U.  S.  Geol.  Survey,  vol.  iv,  p.  728.    Not 

of  Swallow,  1860.    Trans.  St.  Louis  Acad.  Sci.,  vol.  i,  p.  639. 
Calvini  Miller,  1883.    Cat.  Amer.  Pal.  Foss.,  2d  ed.,  p.  298. 

The  author  describes  this  species  as  follows: 

"Shell  small,  concavo-convex,  quadrate  in  outline.  Cardinal  extremi- 
ties sometimes  abruptly  produced,  sometimes  rounded.  Ventral  valve  very 
convex,  flattened  on  the  umbo.and  descending  rapidly  to  the  lateral  and 
frontal  margins.  Dorsal  valve  concave,  following  closely  the  curvature  of 
the  other.  Hinge  area  common  to  both  valves,  wider  on  ventral,  finely 
striated.  Foramen  only  sufficiently  developed  to  receive  the  extremities  of 
the  bifid  cardinal  process.  Muscular  scars  faintly  impressed,  not  definitely 
bounded. 

"Surface  of  ventral  valve  ornamented  by  fine  radiating  striae.  From 
three  to  five  very  small  striae  are  implanted  between  pairs  of  more  promi- 
nent, but  very  slender,  filiform,  and  often  slightly  interrupted  ones.  A 
broad,  shallow  mesial  sinus  sometimes  occupies  the  front  half  of  the  valve. 
On  the  dorsal  valve  the  striae  are  subequal,  corresponding  to  the  finer  ones 
of  the  ventral  valve. 

"Length,  9mra;  width,  llmm;  convexity,  5mm." 

The  species  occurs  in  the  Devonian  formation  of  Iowa  and  corresponds, 
from  the  description,  very  closely  with  the  Nevada  form.  The  latter  is  pro- 
portionally a  little  broader  and  slightly  convex  on  the  umbo,  but  does  not 
appear  to  differ  specifically. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Lone  Mountain,  18  miles  northwest  of  Eureka,  and  Comb's  Peak,  Eureka 
District,  Nevada. 

Genus  CHONETES  Fischer. 

It  is  difficult  to  determine  the  specific  relations  of  many  of  the  forms 
of  the  Productidae  and  especially  those  belonging  to  the  genus  Chonetes, 
as  the  shells  are  usually  small  and  depend  largely  on  the  surface  characters 
and  the  presence  of  the  cardinal  spines  for  their  specific  determination. 


FOSSILS  OF  THE  DEVONIAN.  123 

These  features  are  usually  more  or  less  obscured  by  the  complete  or  partial 
exfoliation  of  the  shell,  even  if  it  has  escaped  being  worn  or  macerated 
previous  to  being  embedded  in  the  sediment.  The  varying  conditions  of 
preservation,  if  in  a  pure  limestone,  calcareous  or  argillaceous  shale,  or  in 
an  arenaceous  rock,  also  materially  complicate  the  question  of  the  identity 
of  species  from  various  horizons  and  widely  separated  localities.  The 
identifications  between  the  Nevada  and  New  York  specimens  of  the  same 
species  were  made  with  the  above  conditions  in  view  and  on  a  direct  com- 
parison with  authentic  specimens  in  the  Hall  collection  at  the  American 
Museum  of  Natural  History  in  New  York  City,  most  of  which  wera  used 
in  the  original  diagnoses  of  the  various  species. 

Chonetes  hemispherica  Hall. 

Clwnttes  hemispherica  Hall,  1857.    Tenth  Ann.  Rep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  116, 

and  Pal.  N.  Y.,  vol.  iv,  p.  118,  pi.  xx,  fig.  6,  1867. 
hemispherica  Billings,  1861.     Can.  Jour.,  vol.  vi,  p.  349. 

Nicholson,  1873.     Pal.  Prov.  Ontario,  p.  75. 
Compare  Strophomena  gibbosa  Conrad. 

The  types  of  this  species  are  from  the  Schoharie  grit  and  Corniferous 
limestone  of  the  Upper  Helderberg  Group  of  New  York.  It  is  a  strongly 
marked  form,  and  with  the  exception  of  the  closely  allied  C.  arcuata,  from 
the  Corniferous  limestone,  it  is  not  likely  to  be  confused  with  any  other 
species  from  the  Devonian.  The  Nevada  specimens  have  the  same  ventri- 
cose  or  subhemispheric  ventral  valve,  with  its  prominent  umbo  rising  above 
the  hinge  line.  The  surface  is  largely  exfoliated  from  all  the  specimens  in 
the  collection,  but  sufficient  remains  to  exhibit  the  characteristic  radiating 
striae.  As  far  as  yet  known  it  is  confined  to  the  Lower  Devonian,  and  is 
associated  with  other  well-defined  Upper  Helderberg  forms,  viz :  Produdus 
(P.)  navicellus,  P.  (P.)  truncatus,  Spirifera  raricosta,  .etc. 

Among  the  collections  of  the  Fortieth  Parallel  Exploring  Expedition 
there  is  a  specimen  of  this  species  from  the  summit  of  Cave  Canon,  Pinon 
Mountains,  Nevada. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Lone  Mountain,  1 8  miles  northwest  of  Eureka,  Nevada. 


124  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Chonetes  deflecta  Hall. 
Plate  ii,  figs.  8,  8  a,  b. 

Chonetes  deflecta  Hall,  1857.    Tenth  Ann.  Rep.  N.  T.  State  Cab.  Nat.  Hist.,  p.  149. 
gibbosa  Hall,  1857.     Ibid.,  p.  145. 
deflecta  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  126,  pi.  xxi,  figs.  7a-g,  Sa-c. 

The  shells  referred  to  this  species  are  from  the  Upper  and  Lower  De- 
vonian beds,  and  in  size,  general  form,  convexity  and  surface  markings  are 
specifically  identical  with  the  examples  of  the  species  from  the  Hamilton 
Group  of  New  York.  There  is  considerable  difference  in  the  height  and 
widfft  of  different  shells,  and  also  in  the  strength  of  the  radiating  surface 
striae.  In  the  latter  variation  Chonetes  acutiradiata  Hall  is  directly  connected 
with  C.  deflecta,  as  expressed  in  its  more  transverse  forms.  Some  of  the 
more  coarsely  striated  examples  approach  C.  mucronata,  but  not  sufficiently 
so  to  be  identified  with  that  species. 

Its  vertical  range  is  from  the  Lower  Devonian  —  Upper  Helderberg 
Group  of  New  York,  to  the  Upper  Devonian  =zChemung  Group  of  New 
York 

Formation  and  localities.— Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  west  slope  of  County  Peak,  and  lower  beds  at  Lone  Mount- 
ain, 18  miles  northwest  of  Eureka,  Upper  Devonian  of  Rescue  Hill,  Eureka 
District,  Nevada. 

Chonetes  mucrouata  Hall? 

Strophomena  mucronata  Hall,  1843.    Geol.  Rep.  Fourth  District  New  York,  p  181  and  p. 

180,  fig.  3. 

Chonetes  laticosta  Hall,  1857.    Tenth  Ann.  Rep.  N.  Y.  State  Cab.  Nat.  Hist,  p.  119. 
mucronata  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  124,  pis.  xx,  xxi. 
Nicholson,  1873.    Pal.  Prov.  Ontario,  p.  74. 

Professor  Hall  gave  the  specific  designation  C.  laticosta  to  a  small,  gib- 
bous, coarsely  striated  shell  from  the  Upper  Helderberg  and  Hamilton 
Groups  of  New  Yi.rk,  which  he  subsequently  considered  as  a  variety  of 
Chonetes  mucronatc.  With  this  form  the  Nevada  specimens  are  identified,  as 
none  of  the  larger,  more  finely  striated  examples  are  yet  known  from  the 
Rocky  Mountain  area. 


FOSSILS  OF  THE  DEVONIAN.  125 

The  largest  specimens  from  Nevada  have  a  length  of  4mm ,  and  a  width 
of  6mm,  the  ventral  valve  being  strongly  convex  or  gibbous  and  marked  by 
from  eighteen  to  twenty-two  strong  striae.  There  is  only  one  cardinal 
8}>ine  preserved;  this  is  bent  down  and  directed  outward  subparallel  to  the 
cardinal  margin. 

The  specific  identification  is  made  with  hesitation,  as  the  specimens 
are  somewhat  imperfect,  and  the  large  adult  shells  are  not  present  in  the 
collections  from  Eureka;  still  the  facts  in  favor  of  the  identification  appear 
to  be  much  stronger  than  those  against  it. 

Formation  and  locality. — In  the  upper  beds  of  the  Devonian  limestone 
of  the  foothills  east  of  Sentinel  Mountain  and  the  Sugar  Loaf,  Eureka 
District,  Nevada. 

Chonetes  setigera  Hall. 

Strophomena  setigera  Hall,  1843.    Geol.  Eep.  Fourth  District  of  New  York,  p.  180,  fig.  2. 

Chonetes  setigera  Hall,  1857.   Tenth  Ann.  Hep.  N.  Y.  State  Cab.  Nar.  Hist.,  p.  150.     Hall, 

18G7.     Pal.  N.  Y.,  vol.  iv,  p.  129,  pi.  xxi,  fig.  2;  pi.  xxii,  figs.  1-5. 

This  species  is  associated  with  the  preceding  in  the  same  hand  speci- 
mens of  limestone.  Of  its  occurrence  in  the  Marcellus  shale,  Professor 
Hall  says:  "This  species  occurs  in  the  same  black  shale  with  C.  mucronata, 
and  may  be  distinguished  from  it  by  the  more  numerous  and  more  fre- 
quently bifurcating  striae,  which  are  likewise  more  angular.  The  direction 
of  the  cardinal  spines,  when  present,  is  always  a  characteristic  feature." 

This  comparison  is  equally  accurate  when  applied  to  the  Nevada  speci- 
mens, as  the  specific  characters  are  similar  in  the  eastern  and  western  shells. 
Professor  Hall  gives  Meadville,  Pennsylvania,  as  the  locality  where  it  is 
found  in  the  Chemung  Group,  thus  showing  its  range  upward  from  the  base 
of  the  Hamilton  Group.  As  far  as  known,  it  occurs  only  in  the  upper  beds 
of  the  Devonian,  in  the  Eureka  District. 

Formation  and  locality. — In  the  upper  beds  of  the  Devonian  limestone 
of  the  foothills  east  of  Sentinel  Mountain  and  the  Sugar  Loaf,  Eureka  Dis- 
trict, Nevada. 


126  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Chonetes  macrostriata,  n.  sp. 
Plate  ii,  fig.  13;  pi.  xiii,  figs.  14,  14o-c. 

Shell  varying  in  form  from  tranverse,  subelliptical,  length  and  breadth 
as  2  to  3,  to  subsemicircular,  the  length  and  breadth  as  3.5  to  4.  Hinge- 
line  a  little  shorter  than  the  greatest  width,  in  both  young  and  old  shells. 
Cardinal  angles  obtuse. 

Ventral  valve  varying  from*  moderately  convex,  in  young  shells,  to 
very  convex  or  gibbose  in  the  older  ones.  This  difference  in  convexity  is 
also  shown  in  older  shells  of  the  same  general  size,  the  more  narrow  indi- 
viduats  being  much  more  convex.  The  outline  of  the  valve  presents  the 
greatest  convexity  on  the  umbo,  the  curvature  to  the  front  and  lateral  mar- 
gins being  regular,  while  it  is  more  rapidly  depressed  towards  the  somewhat 
flattened  cardinal  extremities;  a  feature  noticeable  in  the  younger  shells 
and  strongly  developed  in  the  adults.  Dorsal  valve  more  or  less  conform- 
able in  curvature  to  the  opposite  valve. 

Surface  marked  by  strong,  rounded  striae,  the  spaces  between  them 
being  less  than  their  width.  They  increase  by  intercalation  and  bifurca- 
tion, a  shell  15mm  in  breadth  having  twenty  on  the  lower  part,  and  one  40  "^ 
broad  forty,  the  striae  on  each  having  slight  undulations  in  their  course. 
No  traces  of  concentric  strise  are  to  be  seen. 

The  cardinal  margin  of  the  ventral  valve  in  the  younger  shells  shows 
five  or  six  small  oblique  spines  on  each  side  of  the  apex  that  in  the  older 
shells  are  not  visible  in  any  specimens  in  the  collection.  The  ventral  area 
is  narrow,  linear,  and  has  a  rather  small  foramen  midway  that  is  partially 
closed  by  the  cardinal  process  of  the  opposite  valve.  Dorsal  area  very 
narrow. 

The  imperfect  cast  of  the  ventral  valve  shows  a  bilobed  apex,  formed 
by  the  diverging  dental  lamella  and  narrow  median  ridge,  the  muscular 
impressions  being  obscured  by  adhering  fragments  of  the  shell.  The  por- 
tions of  the  surface  of  the  interior  of  this  and  the  dorsal  valve  that  are 
shown  in  the  specimens  are  finely  papillose,  the  papillae  of  the  dorsal  valve 
being  somewhat  coarser  than  those  of  the  ventral. 

The  variation  between  the  young  and  adult  individuals  of  this  species 


FOSSILS  OF  THE  DEVONIAN.  1  27 

is  so  great  that  the  two  extremes  will  readily  be  taken  as  distinct  species, 
to  avoid  which  an  illustration  is  given  of  the  younger  and  older  shells  with 
an  intermediate  form.  The  outer  surface  of  the  ventral  valve  of  the  shell 
is  exfoliated,  the  characteristic  striae  showing  on  the  dorsal  valve  of  the 
same  specimens. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak;  south  spur  of  Atrypa  Peak;  on  the  divide  of  the  Reese  and 
Berry  Canon,  and  midway  of  Gray's  Canon,  Eureka  District,  Nevada;  also 
at  the  same  horizon  at  the  north  end  of  the  Ravens  Nest,  Pinon  Range, 

Nevada. 

* 

Choiietes  filistriata,  n.  sp. 
Plate  xiii,  figs.  15,  15 a. 

Shell  transverse,  broadly  subelliptical,  varying  in  proportion  from  4  to 
3,  to  3  to  2,  in  breadth  and  length,  respectively;  the  hinge-line  is  a  trifle 
shorter  than  the  greatest  width  of  the  shell,  and  the  cardinal  angles  are  ex- 
tended in  very  short  auriculate  points. 

Ventral  valve  moderately  convex,  the  convexity  varying  but  slightly 
between  the  young  and  old  shells;  the  outline  of  the  valve  is  regularly 
convex,  rising  from  the  cardinal  margin  and  sloping  more  rapidly  from  the 
broad  central  portion  towards  the  front  and  lateral  margins ;  cardinal  margin 
with  three  or  more  short,  slightly  oblique  spines  on  each  side  of  the  apex. 
The  area  is  narrow,  linear,  and  divided  midway  by  a  rather  broad  triangular 
foramen  that  is  nearly  filled  by  the  cardinal  process  of  the  opposite  valve. 

The  dorsal  valve  is  moderately  concave,  following  very  nearly  the 
curvature  of  the  ventral  valve.  Area  linear  and  very  narrow. 

Surface  marked  by  numerous  fine,  closely  arranged  striae,  that  increase 
by  intercalation  and  bifurcation;  they  extend  to  nearly  the  hinge  line  on 
the  cardinal  extremities,  and  vary  in  number  from  80  to  90  on  the  lower 
portion  of  a  medium-sized  shell.  A  few  specimens  show  faint  undulating 
concentric  striae. 

The  specimens  are  all  preserved  in  a  shaly  limestone  and  the  interiors 
of  the  valves  have  not  been  observed. 

Numerous  shells  corresponding  in  general  form  and  size  with  this  spe- 


128  PALEONTOLOGY  OF  THE  EUREKA  DISTEICT. 

cies  occur  at  the  same  locality  a  few  feet  higher  in  the  strata.  Their  sur- 
face, however,  is  smooth,  or  shows  traces  of  very  fine  striae,  a  feature  pro- 
duced probably  by  maceration  or  the  smoothing  of  the  shell  by  attrition 
during  the  life  of  the  animal. 

Of  the  Devonian  species  of  Chonetes  from  the  Devonian  of  the  Missis- 
sippi Basin  or  New  York,  C.  coronata  Conrad  (See  Pal.  N.  Y.,  vol.  iv,  p.  133), 
is  most  nearly  related  to  this  in  general  form.  It  differs  materially  in  the 
coarser  surface  markings,  more  oblique  cardinal  spines,  smaller  ventral 
foramen,  and  greater  convexity. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
•Comrj's  Peak,  Eureka  District,  Nevada. 

Genus  PKODUCTTJS  Sowerby. 
Submenus  PRODUCTELLA  Hall,  R67. 

Productus  (Productella)  subaculeatus  Murch. 
Plate  vii,  fig.  2,  pi.  xiii,  figs.  19,  19  a,  20,  20  a. 

For  list  of  synonyms  see  Davidson's  Monograph  of  British  Devonian  Brachiopoda,  p. 
99,  and  Pal.  X.  Y.,  vol.  iv,  p.  154. 

The  figures  given  by  Murchison  of  the  type  of  this  species10  might  have 
been  taken  from  specimens  from  the  Eureka  District,  so  close  is  the  simi- 
larity between  the  forms  from  the  two  widely  separated  localities.  There 
are  some  slight  variations  in  larger  specimens  but  hardly  sufficient  to  indi- 
cate a  varietal  distinction  in  a  species  of  a  genus  subject  to  so  many  and 
wide  departures  from  what  may  be  considered  the  types  of  some  of  its  most 
typical  species. 

The  illustrations  given  in  the  fourth  volume  of  the  Paleontology  of 
New  York,  plate  xxiii,  are  of  smaller  shells  than  those  from  Nevada,  but  ap- 
pear to  be  specifically  identical  with  them,  while  the  four  referred  to  this 
species,  with  a  query,  from  the  Devonian  limestone  of  Nevada  (Geol.  Expl. 
Fortieth  Parallel,  vol.  iv,  p.  36),  are  evidently  referable  to  a  variety  of 
Hall's  P.  (P.)  Shumardianus. 

Professor  Hall  identifies  P.  (P.)  subaculeatus  in  the  Upper  Helderberg 

10 Bull,  de  la  Soc.  Geol.  de  France,  vol.  xi,  p.  255,  pi.  ii,  figs.  9 a,  b,  c. 


FOSSILS  OF  THE  DEVONIAN. 


129 


limestone,  and  states  that  he  does  not  know  of  its  occurrence  in  the  Hamil- 
ton and  Chemung  Groups  of  New  York. 

In  Europe  it  has  a  wide  vertical  range  in  the  Devonian  formation,  and 
its  geographic  range  is  very  great. 

There  appears  to  be  considerable  confusion  in  regard  to  the  relations 
of  this  species  and  P.  (P.)  Shumardianus  of  Hall,  and  also  with  several 
European  forms  that  have  been  identified  with  it.  There  can  hardly  be  any 
doubt  of  the  identity  of  the  specimen  figured  on  plate  xiii,  figs.  20,  20a,  the 
one  given  by  Murchison  in  his  original  description  of  the  species,  and  the 
adjoining  figures,  19,  ly«,  of  the  Nevada  specimen  which  is  associated  in  the 
same  layer  of  rock  with  specimens  which  unite  it,  by  a  series  of  examples, 
with  the  typical  forms  of  P.  (P.)  Shumardianus  as  they  occur  in  the  Burling- 
ton sandstone  of  Iowa.  At  present  it  is  not  practicable  to  give  the  neces- 
sary illustrations  to  show  the  passage  from  this  species  to  several  forms  now 
considered  as  distinct,  but  it  is  anticipated  that  the  opportunity  will  be  af- 
forded in  the  future  and  that  larger  collections  will  be  accessible  from  the 
Devonian  of  the  Rocky  Mountain  region. 

Formation  and  localities. — Lower,  middle,  and  upper  horizons  of  the 
Devonian  limestone,  west  slope  of  County  Peak;  Rescue  Hill;  mouth  of 
Packer  Basin,  and  at  The  Gate  northwest  of  Eureka,  Eureka  District, 
Nevada. 

Productus  (P.)  subaculeatus  also  occurs  in  the  Lower  Carboniferous  of 
the  Eureka  District. 

Productus  (Productella)  Shumardianua  Hall. 
Plate  xiv,  fig.  1. 

Productus  snumardianus  Hall,  1858.     Geol.  Eep.  Iowa,  vol.  i,  pt.  2,  p.  499,  pi.  iii,  fig. 

9;  pi.  vii,  fig.  1. 
spinulicostce  (in  part)  Hall,  1857.    Tenth  Ann.  Kep.  N.  Y.  State  Cab.  Nat. 

Hist.,  p.  173. 
concentricus  Hall,  1857.     Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist., 

p.  180;  Geol.  Eep.  Iowa,  vol.  i,  pt.  2,  p.  517,  pi.  vii,  fig.  3. 
pyxidatus  (partim  vel  totum)  Hall,  1858.     Geol.  Eep.  Iowa,  vol.  i,  pt.  2,  p. 

498,  pi.  3,  figs.  8a-e. 
Productella  shumardiana  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  157,  pi.  xxiii,  figs.  6-8. 

With  the  views  expressed  in  relation  to  this  species,  in  the  remarks  on 
P.  (P.)  subaculeatus,  it  is  unnecessary  to  state  why  they  are  considered  as 

9  O  D   W 


130  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

closely  allied  and  probably  identical  species.  This  form  ranges  throughout 
the  Devonian  limestone  of  the  district  and  occurs  in  the  lower  beds  at  Lone 
Mountain,  18  miles  northwest  of  Eureka. 

The  \7ariety  P.  (P.)  pyxidatus  is  found  in  both  the  lower  and  upper 
beds.  It  does  not  appear  to  be  specifically  distinct  from  the  form  referred 
to  P.  (P.)  Shumardianus. 


Froductus  (Productella)  Hallanus,  n.  sp. 
Plate  xiii,  figs.  17,  17a. 

Productus  dissimilis  Hall,  1858.    Geol.  Sep.  Iowa,  vol.  i,  pt.  2,  p.  497,  pi.  iii,  figs.  7a-e. 
dissimilis  Meek,  1868.    Trans.  Chicago  Acad.  Sci.,  vol.  i,  p.  91,  pi.  xiii,  fig.  3. 
Not  Productus  dissimilis  De  Koninck,  1846. 

Shell  semielliptical  or  suborbicular,  with  the  length  and  breadth 
usually  nearly  equal,  although  in  some  instances  it  is  transversely  ellipti- 
cal. Hinge  line  shorter  than  the  greatest  width  of  the  shell. 

Ventral  valve  strongly  convex,  ventricose  on  the  upper  part,  which 
projects  slightly  over  the  hinge  line  at  the  umbo  and  terminates  in  a  slightly 
incurved  beak;  the  sides  are  a  little  depressed  towards  the  somewhat  auric- 
ulate  cardinal  extremities.  Area  extremely  narrow  and  rarely  seen  even  on 
well  preserved  shells.  Dorsal  valve  concave,  following  the  curvature  of 
the  opposite  valve. 

Surface  of  ventral  valve  marked  by  fine  radiating  stria3  that  are  slightly 
irregular  in  their  course,  as  if  deflected  by  the  few  scattered,  scarcely  per- 
ceptible spine  bases.  The  dorsal  valve  shows  no  radiating  stria?,  but  strong 
subimbricating,  concentric  lines  give  a  striking  appearance  in  constrast  with 
the  radiating  striae  of  the  ventral  valve. 

The  type  specimens  of  Professor  Hall's  P.  (P.)  dissimilis  were  from 
the  Hamilton  Group,  at  or  near  Rockford,  Iowa,  and  present  all  the  char- 
acters mentioned  in  the  above  description,  which  was  drawn  from  the 
Nevada  specimens.  The  specific  identity  of  the  two  forms  is  very  close, 
and  does  not  permit  of  a  separation  on  any  differences  presented  by  the 
specimens  now  before  me.  As  the  name  given  by  Professor  Hall  was  pre- 
occupied by  a  species  of  the  same  generic  relations  from  the  Devonian 


FOSSILS  OF  THE  DEVONIAN.  131 

rocks  of  Belgium,  a  new  specific  designation  is  given  in  honor  of  the  origi- 
nal discoverer  of  the  species 

Formation  and  localities. — Lower  and  upper  horizons  of  the  Devonian 
limestone,  west  slope  of  County  Peak,  and  Rescue  Hill,  Eureka  District, 
Nevada. 

Productus  (Productella)  navicella  Hall. 
Plate  xiii,  fig.  9. 

Productus  navicella  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  172. 
Productella  navicella  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  156,  pi.  xxiii,  figs.  1-3,  9-11. 

The  specimens  referred  to  this  species  from  the  Upper  Helderberg  and 
Hamilton  Groups  of  New  York  are  distinguished  by  their  narrow,  elon- 
gate form,  extreme  arcuation,  and  strong  costse  on  the  lower  half  of  the 
shell  that  are  extended  upward  as  little  ridges  formed  by  the  spine  bases. 
The  specimens  representing  the  species  in  Nevada  are  a  little  more  elongate 
than  the  average  of  the  New  York  forms,  and  the  radiating  costse  are  some- 
what stronger,  otherwise  the  two  are  identical. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
south  ridge  of  Atrypa  Peak,  Eureka  District,  Nevada. 

Productus  (Productella)  truncatus  Hall. 
Plate  xiv,  fig.  2. 

Productus  truncatus  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  171. 
Strophomena  pustulosa  Hall,  1843.    Geol.  Eep.  Fourth  District  New  York,  p.  18. 
Productella  truncata  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  160,  pi.  xxiii,  figs.12-24. 
Not  Productus  pustulosus  Phillips. 

This  pretty  little  species  occurs  in  the  Lower  Devonian  beds,  and  pre- 
sents the  characters  of  the  specimens  from  the  Marcellus  shale  of  New  York. 

In  his  remarks  on  this  species,  Professor  Hall  states  that,  on  the  author- 
ity of  M.  de  Verneuil,  Strophomena  pustulosa,  a  species  founded  apparently 
on  a  dorsal  valve  of  this  species,  has  been  referred  to  Productus  (Stropha- 
losid)  MurcMsonianus  M.  de  Koninck,  which  is  likewise  regarded  as  iden- 
tical with  the  species  Professor  Hall  described  as  Productus  SJiumardianus. 
Professor  Hall  has  shown  that  P.  (P.)  truncatus  possesses  features  not  ob- 


132  PALEONTOLOGY  OF  THE  EUEEKA  DISTEIOT. 

served  in  P.  (P.)  Shumardianus,  and,  as  it  occurs  in  Nevada,  it  is  very 
distinct  from  the  young  shells  of  the  latter  species.  It  approaches  much 
more  nearly  P.  (P.*)  navicella,  with  which  it  is  associated,  differing  from  that 
very  decidedly  in  its  truncated  apex,  much  less  arcuate  ventral  valve,  and 
broader,  less  elongate  outline.  With  Productus  Murchisonianus  it  appears 
to  present  but  very  few  characters  in  common 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
south  ridge  of  Atrypa  Peak,  and  west  slope  of  County  Peak,  Eureka  Dis- 
trict, Nevada. 

Frodnctus  (Productella)  lachrymosus  var.  limus  Conrad  (Sp.). 

Plate  xiii,  figs.  18,  18  a. 

Strophomena  lima  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Pliilad.,  vol.  viii,  p.  256. 
Productella  lachrymosa  var.  lima  Hall,  1867.     Pal.  N.  Y.,  vol.  iv,  p.  174,  pi.  xxv,  figs. 
29-32. 

This  variety  of  P.  (P.)  lachrymosus  is  well  represented  by  specimens  from 
the  summit  of  the  Devonian  limestone  at  The  Gate,  where  it  is  associated 
with  P.  (P.)  subacukatus  and  P.  (P.)  lachrymosus  var.  stigmatus.  The  median 
depression  of  the  ventral  valve  and  the  characters  of  the  spiniferous  tuber- 
cles are  distinctly  marked,  as  also  the  general  form  and  size  of  the  shell. 

Formation  and  locality. — Devonian  limestone,  at  The  Gate,  northwest  of 
Eureka,  Nevada. 


Productus  (Productella)  lachrymosus,  var.  stigmatus  Hall. 

Productella  lachrymosa  var.  stigmata  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  174,  pi.  xxv, 

figs.  33-41. 
Compare  Productus  f  Meek,  1868.    Trans.  Chicago  Acad.  Sci.,  p.  92,  pi.  xiii,  fig.  5. 

This  strongly  marked  variety  is  represented  by  a  fine  series  of  speci- 
mens that  present  it  as  fqund  in  the  Chemung  Group  of  New  York  and  also 
pass  towards  a  more  costate  variety  that,  in  this  respect,  draws  near  the  true 
species  P.  (P.)  lachrymosus,  but  in  size  and  general  appearance  it  is  more 
nearly  related  to  the  var.  stigmatus.  The  costse  or  plications  are  not  formed 
by  the  elongation  of  the  spine  bases  but  by  the  plication  of  the  shell,  and 


FOSSILS  OF  THE  DEVONIAN.  133 

present  various  stages  of  development,  from  a  simple  trace  on  the  front 
margin  to  where  they  pass  up  over  the  center. 

The  form  from  the  Mackenzie  River  Basin,  illustrated  by  Mr.  Meek  and 
not  specifically  identified,  is  very  closely  related  to  the  semicostate  variety, 
if  not  identical  with  it,  and  it  occurs  in  association  with  Rhynchondla  castanea, 
a  form  found  with  P.  (P.)  lachrymose  var  stigmatus,  at  Rescue  Hill. 

Formation  and  localities. — Upper  horizon  of  the  Devonian  limestone, 
Rescue  Hill,  and  The  Gate,  northwest  of  Eureka,  Nevada. 


Productus  (Productella)  speciosus  HalL 
Plate  xiii,  fig.  8. 

Productus  speciosus  Hall,  1857.    Tenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  176. 
Productella  speciosa  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  175,  pi.  xxv,  figs.  1-11. 

This  beautifully  marked  species  occurs  in  the  same  beds  with  the  vari- 
eties of  P.  (P.)  lackrymosa,  but  it  is  so  distinctly  characterized  by  a  narrow, 
somewhat  attenuate  utnbo  and  the  closely  arranged  smaller  and  more  numer- 
ous spiniferous  tubercles  that  there  is  little  danger  of  confounding  the  two 
species.  Of  the  identity  of  the  New  York  Chemung  Group  specimens  and 
those  from  the  Eureka  District  there  is  hardly  an  opportunity  to  suggest  a 
point  in  opposition,  as  they  closely  coincide  in  all  their  specific  characters. 

Formation  and  localities. — Upper  horizon  of  the  Devonian  limestone, 
Rescue  Hill,  and  at  The  Gate,  northwest  of  Eureka,  Nevada 


Productua  hirsutiforme,  n.  sp. 
Plate  ii,  figs.  10,10  a. 

Shell  thin,  transversely  semicircular;  width  less  than  the  length,  unless 
distorted  by  compression ;  hinge  line  equaling  or  a  little  less  than  the  width 
of  the  shell. 

Ventral  valve  moderately  convex  and  without  median  sinus,  rather 
abruptly  depressed  toward  the  cardino-la^eral  margins,  which  are  flattened 
and  broadly  auriculate;  beak  small,  incurved.  Dorsal  valve  concave  and 
following  the  curvature  of  the  ventral  one. 


134  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

Surface  marked  by  closely  arranged,  slightly  undulating,  concentric 
striae  and  slight  undulating  ridges  of  growth  in  some  examples.  A  few  slen- 
der curved  spines  are  scattered  irregularly  over  the  surface. 

The  interior  of  the  ventral  valve  is  minutely  papillose  throughout; 
other  interior  characters  unknown. 

It  is  with  hesitation  that  a  new  specific  name  is  given  to  a  species  of 
this  genus,  owing  to  the  range  of  specific  variation  within  it.  As  indicated 
by  the  name,  the  species  is  related  to  P.  Mrsuta  Hall  of  the  Chemung  Group 
of  New  York.  It  differs  in  the  surface  characters.  It  has  a  few  minute 
scattered  spines  on  a  comparatively  smooth  surface,  while  P.  hirsuta  has  fine 
spines  with  elongate  bases  over  the  entire  surface,  and  also  a  row  of  long 
spines  near  the  cardinal  border. 

Formation  and  localities — Upper  Devonian,  White  Pine  shale,  on  the 
south  slope  of  Diamond  Peak,  Eureka  District,  and  also  at  the  same  geologic 
horizon  throughout  the  shale  on  the  east  side  of  Applegate  Cafion,  White 
Pine  Mining  District,  Nevada. 


Genus  SPIEIFEEA  Sowerby. 

Spirifera  disjuncta  Sowerby,  1840. 

Synonyms:  See  Davidson's  Monograph  of  British  Devonian  Brachiopoda,  and  Paleon- 
tology of  New  York,  vol.  iv,  p.  243.    To  this  there  may  be  added: 
Spirifera  Norwoodi  Meek,  I860.    Proc.  Acad.  Nat.  Sci.  Philad.,  vol.  xii,  p.  308  (not  8. 

Norwoodi  Hall). 

Utahensis  Meek,  1860.    Note  appended  to  extra  copies  of  above  cited  paper. 
Kennicotti  Meek,  1868.    Trans.  Chicago  Acad.  Nat.  Sci.,  vol.  i,  p.  101,  pi.  xiv, 

fig.  9. 

Utahensis  Meek,  1876.    Eep.  Expl.  Great  Basin  of  Utah,  Simpson,  p.  345,  and 
Geol.  Expl.  Fortieth  Par.,  1877,  vol.  iv,  p.  39,  pi.  iii,  figs.  la-e. 

The  types  of  Mr.  Meek's  Spirifera  Utahensis  were  collected  at  The 
Gate,  northwest  of  Eureka,  and  cited  as  coming  from  a  dark  limestone  of 
Devonian  age,  in  longitude  115°  26'  W.,  latitude  39°  30'  N.,  a  locality 
named  Swallow  Canon  by  Captain  Simpson,  and  now  known  as  The  Gate. 
From  this  locality  a  number  of  very  perfect  specimens  were  obtained  by 
the  Eureka  Survey.  They  exhibit  the  narrow,  rotund  form,  and  also  the 
short  form  with  extended  lateral  angles.  The  examples  of  the  species  used 


FOSSILS  OF  THE  DEVONIAN.  135 

by  Mr.  Meek  were  small,  but  do  not  differ  from  specimens  of  the  same  size 
found  at  Newark  Mountain  or  specifically  from  the  larger  shells  that  are 
identical  with  examples  of  the  species  found  in  New  York  and  also  in  Eng- 
land. 

Formation  and  localities. — Central  and  upper  portions  of  the  Devonian 
limestone,  Newark  Mountain,  and  at  The  Gate,  northwest  of  Eureka,  Ne- 
vada. 

Spirifera  raricosta  Conrad  (Sp.). 
Plate  iv,  figs.  2,  2  a;  pi.  xiv,  fig.  12. 

Delthyris  raricosta  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p.  262,  pi. 

xiv,  fig.  18 

undulatm  Vanuxein,  1842.    Geol.  Eep.  Third  District  New  York,  p.  132,  fig.  3. 
Spirifera  raricosta  Billings,  18C1.    Can.  Jour.,  vol.  vi,  p.  258,  figs.  71-73  of  p.  259;  Pal. 

Fossils,  1874,  vol.  ii,  pt.  1,  p.  47,  pi.  3  A,  figs.  5,  5  a,  b. 
Hall,  1867.    Pal.  New  York,  vol.  iv,  p.  192,  pi.  xxvii,  figs.  30-34,  pi. 

xxx,  figs.  1-9. 
Nicholson,  1873.     Pal.  Prov.  Ontario,  p.  82. 

A  species  closely  allied  to  this,  if  not  identical,  occurs  in  the  lower 
fossiliferous  horizon  of  the  Devonian  limestone.  It  differs  in  not  having 
quite  as  distinct  concentric  strise,  and  also  in  the  absence  of  the  prominent 
septum  shown  in  casts  of  the  ventral  valve  of  specimens  from  the  Schoharie 
grit  of  New  York.  These  are  characters  that  are  variable  in  the  New  York 
forms,  and  do  not  afford  data  for  the  establishment  of  a  distinct  species  on 
the  examples  thus  far  obtained  in  Nevada. 

At  the  East  this  species  ranges  through  the  Schoharie  grit  and  Cor- 
niferous  limestone  of  the  Upper  Helderberg  Group,  and  its  known  geo- 
graphical extension  carries  it  west  from  New  York  across  the  State  of  Ohio 
to  Southern  Indiana  and  northwest  into  Canada  West. 

A  larger  series  of  specimens  from  Lone  Mountain,  collected  a  year 
after  the  above  was  written,  show  a  gradation  in  form  from  Spirifera  rari- 
costa to  S.  duodenaria,  the  constant  differences  in  the  median  sinus  and  fold 
alone  serving  to  distinguish,  in  external  characters,  the  two  species. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Eureka  District,  and  Lone  Mountain,  18  miles  northwest  of 
Eureka,  Nevada. 


136  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT, 

Spirifera  varicosa  Hall. 

Spirifer  vaticosus  Hall,  1857.    Tenth  Ann.  Rep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  130. 

Ibid.,  Description  of  New  Pal.  Fossils,  p.  90,  1857. 
Spirifera  varicosa  Hall,  1867.    Pal.  New  York,  vol.  iv,  p.  205,  pi.  xxxi,  figs.  1-4. 

Ventral  valve  transverse,  semielliptical ;  length  less  than  one-half  the 
width,  lateral  extremities  pointed;  strongly  convex,  most  prominent  on  the 
umbo;  mesial  sinns  strongly  defined,  rounded  on  the  bottom  and  continued 
to  the  apex  of  the  beak;  beak  narrow  and  slightly  incurved.  Area  equal 
to  one-half  the  width  of  the  valve;  it  is  flat  below  and  a  little  concave 
towards  the  apex;  the  fissure  is  high  and  large. 

Surface  marked  by  eight  or  nine  simple,  slightly  angular  plications  on 
each  side  of  the  mesial  sinus,  and  with  fine  radiating  stria?  near  the  umbo, 
where  the  only  fragment  of  the  outer  surface  is  preserved,  the  remaining 
portions  having  been  entirely  exfoliated;  traces  of  strong  concentric  striae, 
however,  are  seen  on  the  lower  part  of  the  cast. 

The  species  represented  by  this  single  valve,  is  a  member  of  a  group 
of  species  illustrated  by  Spirifera  varicosa,  S.  segmenta,  and  8.  arctisegmenta, 
in  the  Upper  Helderberg  limestones  of  the  Falls  of  the  Ohio,  and  in  New- 
York  State.  It  is  related  to  S.  varicosa  by  the  general  form,  the  size  of  the 
area  and  foramen,  and  the  number  of  surface  plications,  and  also  the  fine 
radiating  striae  near  the  umbo;  but,  in  the  absence  of  the  strong  varicose 
concentric  stria?,  a  striking  difference  exists  between  them.  In  the  character 
of  the  plications  the  agreement  is  with  S.  arctisegmenta,  but  the  latter  has  a 
very  narrow  foramen  and  the  area  bending  forward,  features  that  lead  to 
making  a  provisional  reference  to  the  former  species,  as  they  are  considered 
as  of  more  importance  than  the  development  of  the  surface  stria?;  besides 
the  Nevada  shell  shows  traces  of  strong  concentric  stria?  on  the  cast,  and  a 
large  series  of  specimens  would  probably  exhibit  considerable  variation  in 
this  respect.  In  this  event,  or  should  it  prove  to  be  a  distinct  species,  it  adds 
another  member,  by  its  general  character,  to  the  group  of  forms  uniting  the 
fauna  of  the  Lower  Devonian  of  Nevada  and  that  of  the  Upper  Helderberg 
Group  east  of  the  Rocky  Mountain  region. 

Formation  and  locality. — Lower  portion  of  the  Devonian  limestone,  at 
Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


137 


Spirifera  Parryana  Hall? 
Plate  xiv,  fig.  10. 

Spirifer  parryanus  Hall,  1858.    Geology  of  Iowa,  vol.  i,  pt.  2,  p.  509,  pi.  iv,  figs.  8  a,  6. 
Parryana  Billings,  1861.     Can.  Jour.,  vol.  vi,  p.  261,  figs.  77,  78. 

The  original  type  of  this  species  is  from  the  Hamilton  Group  of  Iowa. 
In  all  essential  specific  characters  the  ventral  valve  of  the  Nevada  shell, 
the  only  portion  discovered,  is  similar  to  that  of  the  Iowa  type,  differing 
mainly  in  the  absence  of  the  fine  concentric  strise  crossing  the  radiating 
strise.  Each  of  these  features,  the  simple  radiating  strise  and  the  concentric 
striae,  occur  on  different  specimens  of  an  allied  species,  8.  mesastrialis,  of  the 
Chemung  Group  of  New  York.  The  finding  of  entire  shells  may  afford 
specific  distinctions  not  known  at  present,  but  with  the  present  specimens, 
the  identification  is  made  with  S.  Parryana. 

A  specimen  collected  by  the  geologists  of  the  Fortieth  Parallel  Geo- 
logical Survey,  labeled  "Piiion  Range,"  is  larger  than  the  Eureka  specimens, 
but  otherwise  agrees  with  the  specimen  illustrated. 

Formation  and  locality. — Devonian  limestone,  on  the  divide  at  the  head 
of  the  Reese  and  Berry  Cafion,  Eureka  District,  Nevada. 


Spirifera  (sp.  und't.). 

This  species  is  allied  to  the  group  represented  by  Spirifera  Manni,  of 
the  Upper  Helderberg  Group  of  New  York  and  Ohio.  The  ventral  valve  is 
subpyramidal,  the  height  nearly  equaling  one-half  the  length.  Apex  slightly 
projecting  over  the  area.  Mesial  sinus  well-defined,  reaching  to  the  apex. 
Area  elevated,  slightly  concave  above;  fissure  open  to  the  apex,  about  twice 
as  long  on  the  sides  as  the  width  at  the  base. 

Surface  marked  by  six  or  seven  subangular  or  rounded  plications  on 
each  side  of  the  median  sinus.  Finer  surface  markings  unknown,  owing  to 
the  exfoliation  of  the  shell. 

Owing  to  the  fact  that  species  of  this  genus  undergo  great  variations,  and 
that  our  material  is  unsatisfactory,  no  specific  reference  is  made  of  this  shell. 

Formation  and  localities. — Devonian  limestone,  Comb's  Peak,  Eureka 
District,  and  Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


138  PALEONTOLOGY  OF  THE  EUKEKA  DISTEICT. 

Spirifera  Bnglemanni  Meek. 

Spirifera  Bnglemanni  Meek,  1860.    Proc.  Acad.  Nat.  Sci.  Philad.,  vol.  xii,  p.  308. 

Meek,  1876.    Rep.  Expl.  Great  Basin  of  Utah  (Simpson),  p.  346, 

pi.  i,  figs.  1  Or-c.     (Not  8.  Englemanni,  M.  &  W.) 
Meek,  1877.    Rep.  Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  41,  pi. 
iii,  figs.  3a-e. 

The  original  specimens  of  this  species  were  found  at  The  Gate,  north- 
west of  Eureka,  by  Colonel  Simpson's  exploring  party,  and  subsequently 
Mr.  Arnold  Hague  obtained  examples  from  the  White  Pine  Mountains  south- 
east of  the  Eureka  District. 

The  specimens  in  the  present  collection  came  from  Newark  Mountain, 
in  the  upper  portion  of  the  Devonian  limestone,  and  present  the  essential 
characters  given  by  Mr.  Meek  in  his  description  of  the  species. 

Spirifera  Finonensis  Meek. 
Plate  iv,  figs.  1,  la-/. 

Spirifer  (Trigonotreta)  Pinonensis  Meek,  1870.  Proc.  Acad.  Nat.  Sci.  Philad.,  vol.  xxii, 
p.  60.  Ibid.,  1877,  Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  45,  pi.  i,  figs.  9 a,  b. 

Spirifera  (Trigonotreta)  argentarim  Meek,  1877.  Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p. 
42,  pi.  iv,  figs.  4  a-b. 

This  species  ranges  from  the  base  to  the  summit  of  the  Devonian 
limestone,  throughout  the  Eureka  District,  and  also  occurs  in  the  Pinon 
Mountains,  where  the  original  types  described  by  Mr.  Meek  were  collected. 
In  the  White  Pine  Mountains  the  variety  described  as  S.  (T.)  argentarim 
Meek  is  found  in  the  Middle  and  Upper  Devonian.  The  species  8.  Pino- 
nensis was  founded  on  the  larger,  more  coarsely  ribbed  variety.  Among 
the  large  series  collected  in  the  Pinon  Range  a  shading  off  into  the  smaller, 
finer  ribbed  form  is  observed,  and  among  the  still  more  extensive  series  from 
the  Eureka  District  the  gradation  of  form  and  characters  between  the  type 
of  S.  Pinonensis  and  P.  argentarius  is  complete. 

Formation  and  localities. — The  species  ranges  throughout  the  Devonian 
limestone,  having  been  found  in  the  upper  beds  south  of  The  Gate  and  at 
Newark  Mountain ;  at  the  lower  horizon  it  occurs  at  Comb's  Peak ;  Atrypa 
Peak;  Lone  Mountain,  18  miles  northwest  of  Eureka,  etc.,  Eureka  District; 
also  at  the  west  base  of  Mount  Argyle,  White  Pine  District,  Nevada. 


DOSSILS  OF  THE  DEVONIAN. 


139 


Subgenus  MARTINIA  McCoy. 

Spirifera  (Martinia)  glabra  Martin. 
tor  list  of  synonyms,  see  British  Carboniferous  Brachiopoda,  Davidson,  vol.  ii,  p.  59. 
Spirifera  M.  glabra  is  mentioned  by  Mr.  Davidson  in  his  monograph  of 
the  British  Carboniferous  Brachiopoda,  p.  62,  as  occurring  in  Devonian  rocks, 
and  he  also  states  that  he  had  specimens  from  the  Devonian  of  Devonshire 
which  appeared  undistinguishable  from  those  in  the  Carboniferous  limestone. 
Before  reading  this  observation  we  had  compared  the  Devonian  specimens 
from  Nevada  with  examples  of  S.  (M.)  glabra  from  the  Carboniferous  lime- 
Stone  of  England,  and  also  with  Mr.  Davidson's  beautiful  illustrations  of  the 
species,  and  concluded  that  they  were  at  the  most  but  a  variety  of  the  same 
species,  and  it  is  only  for  convenience  in  referring  to  the  Nevada  Devonian 
form  that  a  varietal  name  is  proposed. 

Spirifera  (M.)  Franklini  Meek,  1869  (Trans.  Chicago  Acad.  Sci.,  vol.  i, 
p.  107,  pi.  xiv,  fig.  12),  is,  as  mentioned  by  Mr.  Meek,  closely  related  to  S. 
(M.}  glabra,  and  with  the  original  specimen  before  me  to  compare  with  the 
Nevada  shells  and  Mr.  Davidson's  figures  of  the  species,  it  scarcely  appears 
to  be  more  than  a  variety,  if  even  that,  of  S.  (M.)  glabra.  Mr.  Meek  sepa- 
rated it  from  S.  (M.  ^glabra  on  account  of  having  the  lateral  margins  of  the 
area  of  the  ventral  valve  extending  out  part  way  parallel  to  the  hinge  mar- 
gins, instead  of  sloping  regularly  from  the  beak  to  the  extremities  of  the 
hinge.  In  the  variety  to  be  next  described  both  characters  occur  on  the 
area  of  the  ventral  valve  on  different  specimens,  so  that  it  is  scarcely  a 
good  specific  distinction. 


Spirifera  (M.)  glabra,  var.  Nevadensis,  n.  var. 
Plate  iii,  fig.  5 ;  pi.  xiv,  figs.  14,  14  a,  6. 

The  range  of  variation  among  the  specimens  in  the  collection  is  con- 
siderable, as  they  differ  in  the  strength  and  angularity  of  the  mesial  fold 
and  sinus,  and  the  depression  along  the  middle  of  the  mesial  fold  of  the 
dorsal  valve  may  be  strong  as  in  the  example  illustrated  on  plate  xiv,  fig. 
14,  or  entirely  absent  even  in  large-sized  specimens.  Some  shells  are  also 


140  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

much  more  transverse  than  others  and  the  relative  length  of  the  hinge  line 
varies. 

The  surface  is  usually  smooth,  owing  to  the  condition  of  preservation 
of  the  shell.  Examples  show,  however,  that  it  was  marked  in  some  instances 
by  obscure  radiating  plications,  concentric  striae  about  I™"1  distant,  also  fine 
radiating  interrupted  striae.  These  vary  in  different  shells  and  in  some  are 
entirely  absent. 

The  variety  differs  from  the  typical  specimens  of  S.  (M.)  glabra  in  having 
the  greatest  transverse  diameter  higher  up  on  the  shell,  and  the  mesial  fold 
and  sulcus  usually  more  angular.  It  also  averages  smaller  in  size,  the  larg- 
est specimen  having  a  height  of  30mm,  with  a  breadth  of  38mm,  and  the  aver- 
age about  25mm  by  30mm. 

Professor  Hall  compares  S.  (M.)  glabra  and  S.  (M.)  Icevis  of  the  Devonian 
of  New  York,  and  more  recently  the  latter  has  been  considered  a  variety 
of  S.  (M.)  glabra,11  a  reference  that  I  would  concur  in,  placing  it,  the  Ne- 
vada variety,  and  Mr.  Meek's  S  (M.}  Franklini,  from  British  America,  as 
the  three  known  representatives  of  the  Carboniferous  species  in  the  Devo- 
nian rocks  of  the  eastern  and  western  side  of  the  continent. 

Formation  and  localities. — Upper  portion  of  the  Devonian  limestone,  on 
the  ridge  east  of  Yahoo  Canon,  and  on  the  south  side  of  The  Gate,  north- 
west of  Eureka,  Eureka  District,  Nevada. 

The  above  was  written  in  1881,  as  the  result  of  the  study  of  the  spec- 
imens then  in  the  collection.  In  the  summer  of  1882  I  returned  to  the 
locality  and  obtained  a  number  of  good  specimens,  some  of  which  have 
faintly  defined  radiating  plications,  thus  showing  that  those  represented  on 
fig.  14&,  plate  xiv,  were  not  the  result  of  irregular  exfoliation  of  the  outer 
shell,  but  a  portion  of  the  original  surface.  An  additional  figure,  plate  iii, 
fig.  5,  is  given  of  a  less  transverse  specimen  than  that  represented  on  plate 
xiv,  figs.  14,  14  a,  b.  This  is  of  the  same  character  as  that  of  S.  (J£)  undifera, 
from  the  Lower  Devonian,  plate  iii,,  figs.  6,  6  a.  The  relations  of  S.  (M.) 
glabra  and  S.  (M.)  undifera  will  be  spoken  of  in  the  description  of  the  latter 
species. 

11 H.  S.  Williams'  Life  History  of  Spirifera  Icevis,  Ann.  New  York  Acad.  Sciences,  vol.  ii,  1881. 


FOSSILS  OF  THE  DEVONIAN. 


141 


Spirifera  (M.)  Maia  Billings. 
Plate  iii,  figs.  1,  la-e;  pi.  xiv,  figs.  13,  13o. 

Athyris  Maia  Billings,  1860.    Can.  Jour.,  vol.  v,  p.  276,  figs.  33,  34. 

Spirifera  Maia  Hall,  1867.    Pal.  New  York,  vol.  iv.,  p.  416  5  pi.  Ixiii,  figs.  6-13. 

Athyris  (?)  Maia  Nicholson,  1874.    Pal.  Prov.  Ontario,  p.  88. 

Compare  Spirifera subumbona  Hall.  1867.   Pal.N.Y.,vol.iv,p.234,pl.xxxiii,figs.22-30. 

8.  (M.)meristoides  Meek,  1868.    Trans.  Chicago  Acad.  Sci.,  vol.  i,  p.  106, 

and  8.  (M.)  sublineatus  Meek,  ibid.  p.  103. 

Professor  Nicholson  considers  Spirifera  (M.)  Maia,  as  identified  by 
Professor  Hall  as,  probably,  a  distinct  species  from  Athyris  Maia  Billings, 
and  refers  the  Canadian  species  to  the  genus  Athyris,  with  a  query. 

The  specimens  used  by  Professor  Hall  in  his  determination,  three  of 
which  are  illustrated  on  plate  Ixiii  of  vol.  iv,  Paleontology  of  New  York,  are 
now  in  the  Hall  collection  in  the  American  Museum  of  Natural  History, 
New  York  City,  and  are  from  Saint  Mary's,  Canada  West,  the  typical  lo- 
cality of  the  species.  They  exhibit  the  narrow  cardinal  area  and  small  tri- 
angular fissure  mentioned  by  Professor  Hall,  and  also  the  variation  in  form 
from  elongate  to  broad  ovate.  Mr.  Billings  and  Professor  Nicholson  failed 
to  observe  the  cardinal  area  and  fissure  which  is  frequently  almost  entirely 
concealed  by  the  incurved  beak. 

The  Nevada  form  corresponds  with  that  from  Canada  West.  Slight 
differences,  liable  to  exist  in  specimens  of  the  same  species  from  widely 
separated  localities,  are  not  perceptible  in  the  examples  separated  by  an 
interval  of  nearly  1,800  miles,  and  there  are  no  perceptible  variations  in 
form  between  the  specimens  occurring  in  the  Lower  Devonian  horizon  and 
those  of  the  limestone  beds  over  3,000  feet  above. 

When  comparing  the  adult  shells  with  other  species  it  is  noticeable 
that  the  more  transverse  forms  approach  the  type  of  Spirifera  (M.)  lineata, 
also  the  smooth  variety  of  Spirifera  (M.)  undifera.  If  it  were  not  for  the 
large  series  of  specimens  it  would  not  be  difficult  to  select  three  allied  species, 
but,  with  the  intermediate  forms,  there  is  but  one  variable  species  which  is 
closely  allied  to  Spirifera  (M.)  lineata  and  Spirifera  ( M .)  planoconvexus  of  the 
Carboniferous. 

There  is  considerable  variation  of  form  among  the  large  number  of 


142  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT 

specimens  representing  the  young  of  S.  (M.)  Maia  in  the  collections  from  Res- 
cue Hill  and  Sentinel  Mountain.  Those  that  are  broader  than  long,  with  the 
beak  a  little  incurved .  over  the  high,  prominent  area  of  the  ventral  valve, 
are  essentially  identical  with  the  type  specimens  illustrated  by  Professor 
Hall  (Pal.  N.  Y.,  vol.  iv,  pi.  xxxiii,  figs.  2J-30)  from  the  Hamilton  Group 
of  New  York  as  Spirifera  (M.)  subumbona.  Closely  resembling  these  come  the 
forms  described  by  Mr.  Meek  from  the  Devonian  limestone  of  the  Macken- 
zie River  Basin.  As  described  by  him  and  illustrated  (Trans.  Chicago 
Acad.  Sci.,  pp.  103,  106,  pi.  xiv,  figs.  1  a-c  and  2  a-c\  the  two  species  S. 
(M.)  meristoides,  and  S.  (M.)  sublineatus,  appear  to  be  identical  with  the 
New  York  and  Nevada  species.  The  muscular  impression  on  the  cast  of 
the  ventral  valve  shows  the  faint  furrow  in  some  specimens  more  deeply 
impressed,  with  the  flat,  shallow,  lateral  impressions,  as  in  S.  (M.)  sublineata, 
and  in  other  specimens  the  vascular  impressions  are  shown,  as  in  S.  (M.) 
meristoides,  and  the  form  of  S.  (M.}  meristoides  is  similar  to  that  of  a  globose, 
elongate  variety  of  8.  (-M".)  Maia,  that  has  the  beak  closely  incurved.  If 
the  species  are  not  the  same  they  are  at  least  very  closely  allied.  The 
series  of  variations  continue  in  the  direction  of  a  more  elongate  gibbous 
form,  with  the  beak  incurved  over  and  partially  concealing  the  low  area; 
this  feature  also  occurs  in  a  broader  gibbose  variety,  which  is  connected  by 
a  direct  series  of  specimens  with  the  Hamilton  species  S.  (M.}  subumbona. 
The  latter,  as  it  occurs  in  New  York,  is  distinguished  by  the  fine  concentric 
striae  and  minutely  punctate  surface,  although  the  shell  structure  appears  to 
be  fibrous.  The  same  surface  and  shell  structure  is  shown  in  the  young 
shells  of  8.  (M.)  Maia.  At  first  these  were  separated  and  referred  to  S.  (M.) 
subumbona,  but  the  obtaining  of  a  large  number  of  specimens  of  various 
forms  and  size  in  association  with  S.  (M.}  Maia  showed  this  separation  to 
be  a  forced  one.  It  is  possible  that  S.  (M.)  subumbona  is  distinct  from  the 
young  of  S.  (M.)  Maia,  and  until  the  material  can  be  obtained  to  show 
that  in  the  eastern  Devonian  the  young  of  S.  (M.}  Maia  is  identical  with  S. 
(M.)  subumbona,  the  two  specific  names  will  have  to  be  recognized. 

Formation  and  localities. — Devonian  limestone,  Rescue  Hill,  south 
slope  of  Sentinel  Mountain,  west  slope  of  County  Peak,  Eureka  District 
and  Lone  Mountain,  northwest  of  Eureka,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


143 


Spirifera  (M.)  undifera  Eoemer. 
Plate  iii,  figs.  3,  3  a,  I,  6,  6  a;  plate  xiv,  figs.  11, 11  a,  b. 

Spirifer  undiferus  Eoemer,  1844.    Rhein.  Uebergaugseb.,  p.  70  u.  73,  tab.  iv,  figs.  5, 6. 
undiferus  Schnur,  1853.    D  linker's  Palaeoutographica,  vol.  iii,  Bracli.,  Eifel., 
p.  204,  tab.  xxxiv,  figs.  3  a-d. 

Sandberger,  1855.    Bracb.,  Ehein,  Schichtensy stems,  p.  18,  pi.  xxxi, 

fig.  8. 
Spirifera  undifera  Davidson,  1865.    Mon.  Brit.  Devon.  Brach.,  p.  36,  pi.  vii,  figs.  1-10; 

also,  var.  undulata,  ibid.,  figs.  11-14. 
compacts  Meek,  1868.    Trans.  Chicago  Acad.  Sci.,  vol.  i,  p.  102,  pi.  xiv,  figs. 

llo-d. 
undiferus,  var.  Talcwancnsis,  Kayser,  1882.    China,  Richthofen,  vol.  iv,  p.  86, 

tab.  xi,  figs.  1,  1  a-e. 

Compare  Spirifera  Jimbriata  (Conrad,  1842)  Hall,  1867.  Pal.  N.  Y.,  vol.  iv,  p.  214,  pi. 
33;  also,  8.  snbundiferus  M.  &  W.,  1868.  Geol.  Surv.  Illinois,  vol.  iii,  p. 
434,  pi.  x,  figs.  5  a-e,  and  S.  (M.)  Richardsoni  Meek,  1868.  Trans.  Chicago 
Acad.  Sci.,  vol.  i,  p.  104. 

But  one  specimen  of  this  species  was  found  among-  the  Devonian 
Brachiopods  brought  from  the  Eureka  District  in  1880.  That  differed  so 
much  from  a  typical  specimen  of  Spirifera  (M.)  undifera,  kindly  sent  to  me  by 
Mr.  Davidson,  who  received  it  from  Dr.  Roemer,  that  I  gave  it  a  specific 
name  in  manuscript,  comparing  it  to  £  (M.}  fiwibriata  Conrad.  During  the 
field  season  of  1882  a  large  number  of  specimens  were  collected  from  the 
Lower  Devonian  of  the  same  district  that  afford  the  means  for  a  more 
extended  comparison  with  S.  (M.)  undifera  and  S.  ( M. .)  Jimbriata. 

The  variety  shown  by  figs.  11,11  a—b,  of  plate  xiv  (the  original  speci- 
men found  in  1880),  has  the  beak  of  the  ventral  valve  so  closely  incurved 
that  the  narrow  area  and  the  foramen  are  almost  entirely  concealed;  the 
few  broad,  rounded  plications  are  crossed  by  concentric  striae,  with  inter- 
spaces between  of  a  little  over  one  millimeter  in  width;  on  these,  between 
the  striae,  radiating  interrupted  striae  occur  that  are  precisely  similar  to  those 
on  specimens  of  £  (M.)fimbriata  Conrad,  now  before  me,  from  the  Upper  Hel- 
derberg  Group  of  New  York,  except  that  they  are  somewhat  finer.  On  the 
shells  of  this  species  from  the  shales  of  the  Hamilton  Group  these  radiating 
striae  reach  their  maximum  development,  appearing  as  elongate,  radiating 
tubercles  on  the  interspaces  between  the  imbricating  striae.  Among  the 
Eureka  specimens  individuals  occur  that  show  the  concentric  striae  about 


144  PALEONTOLOGY  OF  THE  EUKEKA  DISTK1CT. 

one-half  a  millimeter  distant  from  each  other,  and  others  where  they  are 
crowded  still  more  closely;  in  these  we  have  the  typical  surface  of  8.  (M.) 
undifera.  This  crowding  together  of  the  concentric  striae  is  carried  still 
further  in  8.  (M.)  compacta  Meek,  where  the  radiating  plications  are  also 
more  numerous.  No  one  can  examine  the  beautiful  series  of  forms  given 
by  Mr.  Davidson  on  plate  vii  of  his  Monograph  of  Devonian  Brachiopoda 
without  observing  that  the  range  of  variation  in  the  strength  and  number  of 
the  plications  is  quite  as  great  as  between  the  Nevada  type  illustrated  on 
plate  xiv,  and  the  British  American  form  illustrated  by  Mr.  Meek  (Trans. 
Chicago  Acad.  Sci.,  vol.  i,  pi.  xiv).  The  differences  in  the  height  of  the  area 
between  the  two  last-mentioned  shells  is  of  a  very  decided  character,  but 
among  the  later  collections  examples  occur  that  serve  to  bridge  over  and 
unite  the  two  in  this  respect;  one  specimen  has  an  area  of  the  same  height 
as  the  variety  S.  (M.~)  compacta  (plate  xiv,  figs.  13  ft,  c),  and  another  is  inter- 
•  mediate  (plate  iii,  fig.  5). 

From  Lone  Mountain  there  is  a  shell  of  the  type  of  S.  undifera  that  has 
about  twenty  obscure  plications  on  each  side  of  the  mesial  fold  and  sinus  of 
the  ventral  and  dorsal  valve,  respectively.  These  are  crossed  by  concentric 
striae  and  fine  radiating  interrupted  strise.  Still  another  specimen  has  lost 
all  the  radiating  plications,  and  has  only  the  concentric  striae  and  interrupted 
radiating  strise  (plate  iii,  figs.  3,  3  a,  6).  The  latter  shell  may  readily  be 
identified  with  S.  (M.)  prcematura  Hall,  of  the  Upper  Devonian  of  New 
York,  or  S.  (M.)  pseudolineata  or  S.  (M.)  setigera  of  the  Lower  Carboniferous 
limestone  of  the  Mississippi  Valley.  It  is,  however,  in  our  opinion,  a  pre- 
cursory type  in  the  Lower  Devonian  of  the  shell  we  have  called  S.  (M.) 
glaber,  var.  Nevadensis  (ante,  p.  139),  and  which,  before  the  discovery  of  this 
shell  without  plications,  in  the  Lower  Devonian,  was  considered  the  direct 
lineal  descendant  of  S.(M.}  undifera.  We  cannot,  however,  fail  to  notice  the 
close  correspondence  between  the  variety  of  S.  (M.)  undifera  described  by 
Mr.  Meek  as  S.  (M.)  compacta,  and  the  Carboniferous  S.  (M.}  pinguis  Sow- 
erby,  so  fully  illustrated  by  Mr.  Davidson.  8.  (M.)  Eicliardsoni  Meek,  from, 
the  Devonian  of  British  America,  is  closely  allied  to  the  Lone  Mountain 
shell  having  numerous  radiating  plications. 

From  these  comparisons  it  appears  that  S.  (M.)  undifera  is  the  type  of  a 
widely  distributed  and  very  variable  species.  Among  the  American  varie- 


FOSSILS  OF  THE  DEVONIAN.  145 

ties  we  place  S.  (M.)  fimbriata  Conrad,  S.  (M.)  subundifera  M.  &  W.,£  (M.) 
compacta  Meek,  and  the  Nevada  shell  under  consideration. 

S.  (M.)  undifera  and  curvatus,  var.  undulata,  Roemer,  of  the  Middle  De- 
vonian of  England  and  the  continent  of  Europe,  S.  (M.)  erubescens  Eichwald 
(Leth.  Ross.,  p.  703,  taf.  34,  fig.  18),  S.  {M.}  undifera,  var.  Takwanensis, 
Kayser,  from  the  Devonian  of  China,  and  S.  (M.)  undifera  Ethridge,  from 
Queensland,  all  appear  to  belong  to  the  same  specific  group  and  show 
its  wide  geographic  distribution. 

It  may  be  more  convenient  to  use  the  older  name  S.  (M.}  fimbriata 
Conrad  for  the  variety  with  the  strong  interrupted  striae,  as  it  occurs  in  the 
Lower  Devonian  of  New  York  and  the  Upper  Mississippi  Valley  region, 
and  Roemer's  name  S.  (M.)  undifera  for  the  smoother,  world-wide  distrib- 
uted variety  so  well  illustrated  by  Davidson.  If  so,  all  the  species  men- 
tioned will  fall  under  S.  (M.*)  undifera  with  the  exception  of  8.  (M.)Jimbriata. 

Professor  Hall  (Pal.  N.  Y.,  vol.  iv,  p.  216)  calls  attention  to  8.  (M,) 
setigera  and  S.  (M.)  pseudolineata  as  representing  in  the  Carboniferous  lime- 
stone the  type  of  S.  (M.)  finibriata,  and  Mr.  Davidson  (Mon.  Brit.  Dev. 
Brach.,  p.  08)  states  that  the  resemblances  between  S.  (M.)  undifera  and  the 
Carboniferous  S.  (Jf.)  ovalis  and  S.  (Jf.)  pinguis  are  often  so  striking  as 
almost  to  lead  one  to  believe  that  they  are  all  mere  modifications  in  shape 
of  a  single  species. 

We  have  called  attention  in  describing  S.  (M.)  glaber,  var.  Nevadensis,  to 
Prof.  H.  S.  Williams'  life  history  of  S.  (M.)  l&vis—gldber,  where  he  traces  its 
descent  from  certain  Upper  Silurian  forms  through  S.  (M.)  fimbriata,  S.  (M.) 
Icevis,  S.  (M.)  prcematura,  and  considers  S.  (M.)  pseudolineata  as  carrying  on 
the  type  into  the  Carboniferous.  This  arrangement  we  have  accepted,  but 
the  presence  of  the  type  of  S.  (M.)  pseudolineata  in  the  Lower  Devonian 
suggests  the  view  that  the  two  types  S.  {M.)  undifera  and  S.  glaber  were 
already  differentiated  in  early  Devonian  times,  and  that  the  line  of  descent 
of  S.  (M.)  glaber  and  S  (M.)  pinguis  and  the  group  of  species  that  each 
represent  were  determined  in  the  Upper  Silurian  age.  As  we  have  no  rep- 
resentations of  the  latter  fauna  in  the  West,  further  comparisons  are  omit- 
ted, the  reader  being  referred  to  Professor  Williams'  excellent  paper  for  his 
views  of  the  Silurian  representations  of  the  type  of  Spirifera  under  consid- 
eration (Ann.  New  Yoi;k  Acad.  Sci.,  vol.  ii,  1881). 
10  o  D  w 


146  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Spirifera  (If.)  setigera  occurs  in  the  Lower  Carboniferous  of  the  Eureka 
District,  and  thus  gives  a  direct  local  continuation  in  the  Carboniferous  of 
the  smooth  shell,  fig.  3,  plate  iii,  from  the  base  of  the  Devonian. 

Formation  and  localities. — Spirifera  (Jlf.)  undifera  occurs  in  the  Lower 
Devonian  of  Atrypa  Peak  in  the  Eureka  District,  and  also  at  the  same 
horizon  on  Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


Genus  CYRTINA  Davidson. 

Cyrtina  Davidson!,  n.  sp. 
Plate  iii,  figs.  2,  2  a-e. 

Shell  small;  general  shape  more  or  less  triangular  or  subpyramidal; 
hinge  line  a  little  shorter  than  the  greatest  length  of  the  shell. 
+  Ventral  valve  pyramidal  and  very  much  deeper  than  the  dorsal,  most 
prominent  at  the  beak,  which  varies  in  elevation  and  is  straight  or  a  little 
arched  over  the  area;  area  large,  triangular,  flat  or  slightly  arcuate,  more 
or  less  angular  on  the  lateral  margins;  bent  back  at  varying  angles  to  the 
general  surface  of  the  dorsal  valve;  fissure  long,  narrow,  and  apparently 
arched,  nearly  if  not  quite,  over  by  the  pseudo-deltidium;  the  median  sinus 
is  obsolete  or  else  merely  a  depression  between  two  low,  rounded  plications. 

Dorsal  valve  semicircular  or  depressed  convex;  beak  minute  and  rising 
a  very  little  above  the  cardinal  line;  area  linear,  very  narrow;  medium 
fold  obsolete  or  else  a  low,  rounded  plication  similar  to  those  on  either  side. 

Surface  marked  by  one  or  two  rounded  plications  on  each  side  of  the 
medium  sinus  and  fold,  or  these  may  be  almost  entirely  absent,  showing 
as  slight  undulations  on  the  front  margins  of  the  valves.  Shell  structure 
punctate. 

Dimensions:  width  of  valves  of  largest  example  obtained,  8mm;  height 
of  dorsal  valve,  6mm;  depth  of -ventral  valve,  5mm. 

This  very  pretty  species  of  Cyrtina  is  unlike  any  known  to  me.  The 
range  of  variation  in  the  surface  plications  is  considerable,  but  I  do  not 
think  it  would  pass  into  such  forms  as  C.  heterodita,  a  variety  with  few  pli- 
cations, or  G.  Hamiltonensis. 


PCSSILS  OF  THE  DEVONIAN.  147 

Formation  and  localities. — Middle  and  Upper  Devonian  limestone,  Tele- 
graph Peak,  and  eastern  base  of  Mount  Argyle,  White  Pine  Mining  District, 
Nevada. 

Cyrtina  Hamiltonensis  Hall. 

Cyrtia  hamiltonensis  Hall,  1857.    Tenth  Arm.  Eep.  N.  Y.  State  Cab.  Nat.  Hist,  p.  166. 
Hamiltonensis  Billings,  18G1.    Canadian  Journal,  n.  ser.,  vol.  vi,  p.  262,  figs. 

80-82.    Geol.  Canada,  1863,  p.  384,  figs.  415  a-c. 
Cyrtina  hamiltonensis  Hall,  18G7.    Pal.  N.  Y.,  vol.  iv,  p.  268,  pi.  xxvii,  figs.  1-4;  pi.  xliv, 

figs.  26-33,  38-52. 
Hamiltonensis  Meek,  1869.    Trans.  Chicago  Acad.Sci.,  vol.  i,  p.  99,  pi.  xiv,  figs. 

5,  7,  and  10. 

Hamiltonensis  Nicholson,  1874.    Eep.  Pal.  Prov.  Ontario,  p.  83. 
Compare  Cyrtina  heteroclita  of  authors. 

The  only  specimen  of  this  species  recognized  in  the  Eureka  District 
collection  is  from  the  Upper  Devonian  horizon;  it  is  a  silicified  shell  pre- 
serving the  two  valves  united,  and  below  the  average  size  of  full  grown 
individuals  from  the  Hamilton  Group  of  New  York  and  Canada;  there 
appears  to  be  little  question  of  its  specific  identity  with  them. 

In  the  collection  of  Devonian  fossils  from  the  Mackenzie  River,  Brit- 
ish America,  Mr.  F.  B.  Meek  recognized  this  species  (Trans.  Chicago  Acad. 
Sci.,  vol.  i,  p.  100),  and  he  also  states  that  it  occurs  on  Porcupine  River,  a 
tributary  of  the  Yukon,  longitude  140°  W.,  latitude  67°  N. 

Formation  and  locality. — Upper  Devonian,  at  The  Gate,  northwest  of 
Eureka,  Nevada. 

Genus  NUCLEOSPIEA  Hall. 
Nucleospira  coucinna  Hall. 

Atrypa  concinna  Hall,  1843.    Geol.  Eep.  Fourth  District  New  York,  p.  200,  fig.  3. 
Nucleospira  concinna  Hall,  1859.    Twelfth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  pp.  25 
and  26.    Hid.,  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  279,  pi.  xlv,  figs.  33  to  57. 

This  species  is  a  rare  form  in  Nevada,  having  been  found  but  sparingly 
at  one  locality.  At  the  East  it  has  a  wide  geographic  range  in  the  State 
of  New  York,  and  is  also  found  in  the  States  of  Virginia,  Maryland,  and 

Indiana.     It  ranges  vertically  from  the  Schoharie  grit  up  into  the  Hamilton 
Group. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Lone  Mountain,  northwest  of  the  Eureka  District,  Nevada. 


148  PALEONTOLOGY  OF  THE  EUEEKA  DISTEIOT. 

Genus  ATHYEIS  McCoy. 

Athyris  Angelica  Hall. 

Athyris  angelica  Hall,  1861.    Fourteenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  99. 
Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  292,  pi.  xlvii,  figs.  9-20. 

This  species,  in  New  York,  is  known  only  in  the  Chemung  Group,  a 
horizon  comparable  with  the  upper  beds  of  the  Devonian  of  the  Eureka 
District,  although  the  fauna  is  not  as  specialized  as  in  the  East.  In  all  essen- 
tial particulars  the  specimens  from  these  widely  separated  localities  are 
specifically  identical,  with  the  exception  of  one  feature,  which  has  not  been 
observed  in  the  New  York  examples.  When  the  outer  part  of  the  shell, 
with  the  imbricating  lamella  or  lamelliform  striae  is  exfoliated,  the  entire 
surface  is  more  or  less  marked  by  radiating  striae.  The  form  of  the  shell 
varies,  as  in  the  New  York  specimens,  from  transverse  to  elongate,  the  latter 
usually  prevailing. 

Formation  and  localities. — Devonian  limestone,  The  Gate,  northwest  of 
Eureka,  and  Newark  Mountain,  Eureka  District,  Nevada, 

Athyris  (sp.  undt.).    • 

A  single  specimen  of  this  form  with  the  shell  exfoliated,  except  on  the 
upper  portion,  occurs  at  Lone  Mountain,  low  in  the  Devonian.  It  resem- 
bles Athyris  cora,  of  the  Hamilton  and  Chemung  Groups  of  New  York  (PaL 
N.  Y.,  vol.  iv,  291,  pi.  xlvii,  figs.  1-7),  but  is  probably  a  distinct  species. 

Genus  MEEISTELLA  Hall. 
Genus  WHITFIELDIA  Davidson. 

Meristella  (Whitfieldia)  nasuta  Conrad  (Sp.) 
Plate  iii,  figs.  8,  8  a,  86. 

Atrypa  nasuta  Conrad,  1842.    Jour.  Acad,  Nat.  Sci.  Philad.,  vol.  viii,  p.  265,  figs.  8, 9. 
Meristella  nasuta  Hall,  1860.    Thirteenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  93. 
elissa  Hall,  1861.    Fourteenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  100. 

Ibid.,  186l>.    Fifteenth  Ann.  Eep.,  pi.  iii,  figs.  21,  22. 

nasuta  Hall,  1862.    Fifteenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat.  Hist,  p.  160, 
3. 17-19  of  p.  161. 


FOSSILS  OF  THE  DEVONIAN. 


149 


Athyris  Clara  Billings,  1860.    Canadian  Journal,  vol.  v,  p.  274,  figs.  29-32.    Ibid.,  1863. 

Geology  of  Canada,  p.  373.  figs.  397  a,  b. 

Meristella  nasuta  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  299,  pi.  xlviii,  figs.  1-25. 
Athyris  nasuta  Nicholson,  1874.     Pal.  Prov.  Ontario,  p.  86. 
Compare  Whitfieldia  tumida  Dalman's  (Sp.). 

Professor  Hall  (Pal.  N.  Y.,  vol.  iv,  p.  299)  cites  Atrypa  nasuta  Conrad 
Ann.  Report  on  the  Paleontology  of  New  York,  p.  18.  I  have  not  been 
able  to  find  any  such  reference,  but  find  the  original  description  in  the 
Journal  of  the  Philadelphia  Academy  of  Natural  Sciences,  as  cited  above. 

A  number  of  examples  of  this  species  occur  at  the  Lower  Devonian 
horizon  of  Lone  Mountain,  in  association  with  other  well-known  Upper 
Helderberg  or  Corniferous  limestone  fossils  of  the  eastern  side  of  the  conti- 
nent. None  of  them  attain  the  large  size  of  many  specimens  from  New 
York  and  Canada,  but  their  specific  identity  with  specimens  of  a  corre- 
sponding size  scarcely  permits  of  question.  The  presence  of  a  narrow 
depressed  line  or  median  sinus  on  both  valves  is  a  character  absent  on  Jf. 
nasuta,  but  present  in  the  closely  allied  Whitfieldia  tumida  Dalman  (sp.) 
(Davidson,  1882,  Mon.  Brit.  Foss.  Brach.,  vol.  v,  p.  107)  of  the  Upper 
Silurian.  The  broader  depressed  fold  of  the  dorsal  valve  and  rounded  sinus 
of  the  ventral  valve  are  also  more  characteristic  of  the  latter  species. 

I  am  very  much  inclined  to  identify  this  Nevada  shell  with  Whitfieldia 
tumida,  as  M.  nasuta  is  scarcely  more  than  a  variety  of  it  that  obtains,  in 
its  later  stages  of  growth,  a  greater  prolongation  of  the  valves.  If  either 
the  Nevada  or  New  York  shells  were  found  in  association  with  M.  tumida, 
they  would  scarcely  be  distinguished  in  external  characters  as  more  than  a 
variety.  For  the  purpose  of  more  clearly  presenting  the  relations  of  the 
Devonian  faunas  of  the  Rocky  Mountains  and  the  eastern  half  of  North 
America,  and  while  awaiting  more  material  for  study,  we  have  retained 
species  under  separate  names  that  are  considered  as  varieties  of  some  well- 
known  species. 

Formation  and  locality. — Lower  Devonian  of  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


150  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  ATRYPA  Dalman. 

Atrypa  reticularis  (Linnaeus  sp.)  Dalman. 
Plate  xiv,  figs.  6,  60,  &. 

Synonyms:  See  Davidson's  Monographs  of  the  British  Silurian  and  Devonian  Brachi- 
opoda. 

This  extremely  variable  species  is  represented  by  three  distinct  types 
in  the  collections  from  the  Eureka  District  and  Lone  Mountain. 

The  first  is  a  large,  robust  form  similar  to  that  occurring  in  the  Upper 
Helderberg  limestone  and  Hamilton  shales  of  New  York,  and  designated 
by  Mr.  Vanuxem  as  Hipparionyx  (Atrypa}  consimilaris,  and  is  illustrated  as 
a  variety  of  Atrypa  reticularis  (Pal.  N.  Y.,  vol.  iv,  p.  319,  pi.  lii,  figs.  9-12). 

The  variations  from  this,  as  shown  on  the  following  plate  (foe.  ce£),  also 
occur  at  the  lower  horizon  of  the  Devonian  limestone  at  County  and 
Woodchoppers  Peaks,  Sentinel  Mountain,,  Eureka  District,  and  Lone 
Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

*  The  second  variety  is  more  symmetrical  and  has  very  fine  radiating 
costa3,  resembling  the  variety  from  the  Hamilton  and  Chemung  Groups  in 
the  State  of  Iowa.  The  radiating  costse,  however,  are  finer,  approaching 
in  this  respect  the  radiating  striae  of  the  Silurian  shell  Zygcspira  Headi  Bil- 
lings (Pal.  Ohio,  vol.  i,  p.  127).  It  is  found  in  the  upper  part  of  the  De- 
vonian at  Rescue  Hill,  at  the  mouth  of  Packer  Basin,  and  at  The  Gate,  north- 
west of  Eureka. 

The  third  variety  also  occurs  in  the  higher  beds  of  the  formation  at 
The  Gate  and  east  of  the  Sugar  Loaf.  In  form  it  is  similar  to  the  Silurian 
examples  from  the  Niagara  limestone  of  New  York  (Pal.  N.  Y.,  vol.  ii,  p. 
270,  pi  Iv,  figs.  5  Or-u).  An  illustration  of  it  is  given  on  plate  xiv,  figs.  6, 
6  a,  &,  of  this  report. 

Formation  and  locality. — Throughout  the  Devonian  limestone  of  the 
Eureka  District. 

Atrypa  desquamata  Sowerby. 

< 

Plate  xiv,  figs.  4, 4  c. 

Synonyms:  See  Davidson's  Monograph  of  British  1'ossil  Brachiopoda,  vol.  iii,  pt.  6, 
p.  58,  pi.  xi,  figs.  1-9. 

Several  examples  of  a  species  of  Atrypa,  with  a  distinctly  defined  area 
and  circular  foramen  on  the  ventral  valve,  were  found  in  the  lower  beds  of 


FOSSILS  OF  THE  DEVONIAN. 


151 


the  Devonian  limestone  associated  with  Atrypa  recticularis.  They  are 
readily  separated  from  that  species,  but  not  from  the  young  shell  of  A.  des- 
quamata,  as  illustrated  by  Davidson,  to  which  they  are  specifically  related. 
The  largest  specimen  has  a  length  of  16mm,  width  of  17mm,  and  depth  of  the 
two  valves  of  8mm.  A.  desquamate  is  a  much  larger  and  more  robust  spe- 
cies when  fully  developed,  but  the  similarity  in  the  young  shells  of  the  two 
forms  is  so  strong  that  we  cannot  but  consider  them  as  specifically  identical. 
Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Atrypa  Peak,  south  spur;  and  Lone  Mountain,  18  miles  northwest  of  Eu- 
reka, Nevada. 


Geims  TREMATOSPIRA  Hall. 

Trematospira  infrequens,  n.  sp. 
Plate  iv,  figs.  3,  3  a,  b. 

Shell  transversely  elliptical,  moderately  convex;  hinge  about  three- 
fourths  the  width  of  the  shell. 

Ventral  valve  not  quite  as  convex  as  the  dorsal;  mesial  sinus  well 
defined  from  the  beak  to  the  anterior  margin  and  marked  by  a  single  small 
median  plication;  beak  elevated,  small,  and  truncated  by  a  small  perfora- 
tion. The  dorsal  valve  has  a  low  mesial  fold  outlined  by  two  strong  plica- 
tions. 

Surface  of  the  ventral  valve  marked  by  two  strong  and  one  slight  pli- 
cation each  side  of  the  plication  on  the  edge  of  the  mesial  sinus;  ventral 
valve  by  the  same  number  each  side  of  the  central  plications  of  the  mesial 
fold.  Shell  structure  punctate. 

This  is  a  distinct  and  well-marked  species,  approaching  Trematospira 
camura  Hall,  1 852  (Pal.  N.  Y.,  vol.  ii,  p.  273,  pi.  Ivi,  figs.  3a-t),  of  the  Niag- 
ara Group  and  T.gibbosa  Hall,  1867  (Pal.  N.  Y.,  vol.  iv,  p.  272,  pi.  xlv,  figs. 
7-15)  of  the  Hamilton  Group  of  New  York  more  nearly  than  any  other  spe- 
cies with  which  we  are  acquainted. 

Formation  and  locality. — Lower  Devonian,  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


152  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  BHYNCHONELLA  Fischer. 
Rhynchonella  Horsfordi  Hall. 
Plate  xiv,  fig.  3 ;  plate  xv,  fig.  6. 

Rhynchonella  Jiorsfordi  Hall,  1860.    Thirteenth  Ann.  Rep.  N.  Y.  State  Cab.  Nat.  Hist, 

p.  87. 

(Stenocisma)  horsfordi  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  339,  pi.  liv,  figs. 
24-32. 

A  comparison  of  the  Nevada  forms  of  this  species  with  those  of  the 
same  stage  of  development  from  New  York  prevents  their  specific  separa- 
tion. But  few  specimens  were  found,  and  it  is  not  an  abundant  shell  in  New 
York,  although  occurring  in  the  Marcellus  and  Hamilton  shales. 

Formation  and  locality. — Devonian  limestone,  Atrypa  Peak,  Eureka 
District,  Nevada. 

Rhynchonella  Tethys  Billings. 

Ehynchonella  tethys  Billings,  1860.    Canadian  Journal,  vol.  v,  p.  270,  figs.  20-22. 

(Stenocisma)  tethys  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  335,  pi.  liv,  figs.  1-8. 

This  species  is  very  closely  related  to  the  preceding,  and  in  making  a 
comparison  of  the  two  species  with  the  specimens  from  Nevada,  it  is  difficult 
to  recognize  constant  specific  characters  that  distinguish  them.  Both  species 
are  represented  in  the  collections  by  the  extreme  forms,  and  until  a  large 
number  of  well-preserved  specimens  are  collected,  it  may  be  premature  to 
propose  to  unite  them  in  one  species. 

Formation  and  localities. — In  the  Lower  Devonian  horizon  at  Comb's 
Peak,  and  at  Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

Rhynchonella  f  occidens,  n.  sp. 
Plate  xv,  figs.  3,  3  a,  ft. 

Shell  small,  suboval  to  globose;  strongly  plicated.  Ventral  valve 
slightly  less  convex  than  the  dorsal. 

Ventral  valve  somewhat  convex  above,  becoming  depressed  midway  of 
its  length,  with  a  shallow  sinus  that  extends  down  and  curves  beneath ;  sides 
uniformly  convex  to  the  margins.  Beak  somewhat  elevated  and  curving 


FOSSILS  OF  THE  DEVONIAN. 


153 


over  that  of  the  dorsal  valve.  Dorsal  valve  about  as  wide  as  long,  strongly 
convex,  and  with  a  well-defined  mesial  elevation  on  the  lower  half  of  the 
valve;  sinuate  in  front  to  unite  with  the  projections  of  the  mesial  fold  of  the 
opposite  valve. 

Surface  with  from  eleven  to  thirteen  simple,  angular  plications  that  grad- 
ually increase  in  size  from  the  apex;  of  these  there  are  four  on  the  median 
elevation  and  three  on  the  sinus. 

The  dimensions  of  the  largest  specimen  are:  Length,  8mm;  width,  6mm; 
distance  through  the  greatest  convexity  of  the  shell,  5.5mm ;  of  the  smallest 
specimen:  length,  4mm;  width,  3.75mm;  convexity,  3mm.  The  latter  has  the 
plications  and  the  mesial  fold  and  sinus  developed  as  in  the  larger  shell. 
Other  examples  are  less  convex,  and  with  the  fold  and  sinus  scarcely  defined. 

In  its  general  aspect  this  species  is  similar  to  some  forms  of  the  genus 
Rhynchospira,  and  with  the  discovery  of  more  perfect  specimens  showing 
the  beak  and  area  of  the  ventral  valve,  and  the  interior  spires,  if  they  exist, 
it  may  possibly  be  referred  to  that  genus. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Eureka  District,  Nevada. 


Rhynchonella  castanea  Meek. 
Plate  xv,  figs.  1,  1  a,  4,  4  a. 

Khynchonella  castanea  Meek,  1868.    Trans.  Chicago  Acad.  Sci.,  vol.  i,  p.  93,  pi.  xiii,  figs. 


Shell  subglobose;  ventricose  on  the  dorsal  side,  and  somewhat  flattened 
on  the  ventral;  length  and  breadth  subequal  or  a  little  longer  than  wide. 

Ventral  valve  slightly  convex  on  the  umbo,  flattened  or  slightly  convex 
on  the  sides,  and  with  a  more  or  less  well  defined  sinus  that  is  first  seen 
about  the  center  of  the  valve.  The  sinus  has  from  three  to  six  depressed, 
rounded  plications,  and  varies  in  form  from  the  subquadrate,  linguiform 
extension,  with  subparallel  sides  in  the  smaller  shells,  where  it  is  strongly 
incurved,  to  the  shorter  depression  outlined  by  the  elevated,  acute  margins 
on  the  lower  part  that  is  not  curved  beneath  even  in  large  individuals.  Beak 
abruptly  incurved  over  that  of  the  opposite  valve. 


154  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Dorsal  valve  gibbous,  sloping  somewhat  abruptly  to  the  margins  of  the 
opposite  valve;  mesial  fold  prominent  in  the  younger  shells,  and  marked 
with  three  or  four  plications  that  extend  up  to  the  upper  third  of  the  valve. 
In  older  specimens  the  fold  is  scarcely  traceable  above  the  middle  of  the 
valve,  and  the  plications,  six  or  eight,  are  usually  short  and  confined  to  the 
lower  part. 

Surface  of  younger  shells  with  obscure  plications  on  the  sides  and 
stronger,  depressed,  rounded  plications  on  the  mesial  fold  and  sinus.  Con- 
centric lines  of  growth  mark  the  upper  part  of  each  valve.  The  surface 
of  the  older  shells  is  smooth  with  the  exception  of  the  plications  on  the 
mesial  fold  and  sinus  and  a  few  lines  of  growth. 

This  is  a  somewhat  variable  species  in  its  different  stages  of  growth. 
The  younger  shells  are  subcuboidal  and  of  the  type  of  Wiynclionella  venus- 
tula  Hall  (Pal.  N.  Y.,  vol.  iv,  p.  346,  pi.  liv,  A,  figs.  24-43)  of  the  Tully 
limestone  of  New  York,  while  the  adults  are  subglobose,  with  the  ventral 
valve  less  convex,  and  the  angle  formed  by  the  union  of  the  sides  of  the 
two  valves  more  acute.  The  two  extremes  of  growth  might  readily  be 
separated  as  distinct  in  their  specific  characters.  The  species  is  of  the  type 
of  Rhynchonella  Emmonsi  Hall  and  Whitfield  (Gleol.  Expl.  Fortieth  Par.,  vol. 
x,  p.  247,  pi.  iii,  figs.  4—8)  from  the  Devonian  limestone  of  White  Pine 
Mountains,  Nevada;  but  it  is  specifically  distinct  from  that  species,  and  also 
H.  venustula  and  R.  cuboides  Sowerby  (sp.)  (Davidson,  Mon.  Brit.  Foss. 
Brach.,  vol.  iii,  pt.  6,  p.  65,  pi.  xiii,  figs.  17—21)  of  the  same  group  of  species, 
although  more  or  less  resembling  them  in  some  of  its  phases  of  develop- 
ment. 

The  above  was  written  before  I  had  seen  the  description  and  illustra- 
tion of  Mr.  Meek's  species,  M.  castanea,  from  the  Devonian  limestone  in  the 
Mackenzie  River  Basin.  A  careful  comparison  of  the  Nevada  specimens 
with  Mr.  Meek's  description  and  figures,  leads  to  the  opinion  that  R.  castanea 
is  one  of  the  variations  of  the  species  as  it  occurs  in  the  Eureka  District, 
and  that  the  latter  form  should  be  united  with  it  under  the  same  specific 
designation,  as  also  the  shell  illustrated  by  Mr.  Meek  as  probably  a  distinct 
species  (Trans.  Chicago  Acad.  Sci.,  vol.  i,  plate  xiii,  fig.  10a,  fc),  but  which  is 
the  more  convex  or  subcuboidal  form  of  the  species. 


FOSSILS  OF  THE  DEVONIAN. 


155 


The  locality  of  the  type  of  E.  castanea  is  given  as  Lockhart  River, 
British  America,  latitude,  67°  15';  longitude,  126°  W. 

Formation  and  localities. — Upper  Devonian  limestone  of  Rescue  Hill 
and  the  mouth  of  Packer  Basin,  and  Lower  Devonian  on  the  west  slope  of 
County  Peak,  Eureka  District,  Nevada.  . 

Rhynchoiiella  duplicata  Hall. 
Plate  xiv,  fig.  8. 

Atrypa  duplicata  Hall,  1843.    Kep.  Fourth  Geol.  Dist.  N.  Y.,  Organic  Eemains  of  the 

Cheinung  Group,  No.  67,  figs.  2,  2  a-b. 
Khynclionella  (Stenocisma]  duplicata  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  350,  pi.  Iv,  figs. 

17-25. 

This  species  has  hitherto  been  known  in  only  a  few  localities  of  the 
Chemung  Group  in  New  York.  Its  author  states  that  it  is  usually  about 
three-eighths  of  an  inch  in  length  and  breadth,  rarely  attaining  the  length 
of  half  an  inch  (12.5mm).  The  size  is  less  than  that  of  the  Nevada  speci- 
mens, but  otherwise  the  two  are  in  all  essential  particulars  specifically 
identical.  A  very  perfect  shell  from  the  limestone  east  of  the  Sugar  Loaf 
has  a  length  of  18mm,  with  a  width  of  19mm,  and  corresponds  in  nearly  every 
detail  with  the  type  of  the  species  A  large  number  of  perfect  specimens 
were  collected  at  Rescue  Hill  that  present  slight  differences,  which,  how- 
ever, are  not  considered  of  specific  value.  The  sharp  angular  plications 
and  the  margins  of  the  sinus  on  the  ventral  valve  are  rounded  and  de- 
pressed ;  the  shells  are  broader  than  long,  having  a  proportion  of  6  to  5,  and 
usually  more  ventricose,  which  gives  a  deeper  and  more  incurved  sinus. 

Formation  and  localities. — Devonian  limestone.  Rescue  Hill  and  east 
of  the  Sugar  Loaf,  Eureka  District,  Nevada. 


Rhynchoiiella  puguus  Martin. 
Plate  xiv,  figs.  7,  7a. 

Conchyliolithus  anomites pugnus  Martin,  1809.    Petrificata  Derbiensia,  tab.  xxii,  figs.  4, 5. 
Atrypa  pugnus  Sowerby.    Geol.  Trans.  2d  Series,  vol.  v,  pi.  Ivi,  figs.  15-18. 
Terebratula  pugnus  Phillips,  1841.    Paleozoic  Fossils  of  Devon.,  etc.,  p.  87,  pi.  xxxv, 

figs.  156  a-e. 
anisodonta  Phillips,  1841.    Ibid.,  p.  86,  pi.  xxxiv,  figs.  154  a-c. 


156  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Rhynchonella  pugnus  Davidson,  1861.  Mon.  Brit.  Carb.  Brach.,  p.  97,  pi.  xxii,  figs.  1- 
15.  Ibid.,  Mon.  Brit.  Devonian  Brach.,  1865,  p.  63,  pi.  xii,  figs.  12-14; 
pi.  xiii,  figs.  8-10. 

Missouriensis  Meek,  1866.  Geol.  Survey  Illinois,  vol.  ii,  p.  153,  pi.  xiv, 
figs.  4  a,  b.  Fig.  5  a  of  pi.  C.,  2d  Ann.  Eep.  Geol.  Surv.  Missouri,  1855, 
is  also  referable  .to  Rhynchonella  pugnus,  as  stated  by  Mr.  Meek.  Not 
R.  Missouriensis  Meek,  1868.  Ibid,  vol.  iii,  p.  450,  pi.  14,  fig.  7  a-d. 

alta  Calvin,  1877.  Paper  read  before  the  Iowa  Academy  of  Sciences  and 
a  named  photographed  plate  distributed. 

pugnus  Williams,  1883.    Amer.  Jour.  Sci.,  vol.  xxv,  p.  99. 

The  varietal  differences  among  the  Nevada  specimens  from  the, same 
layer  or  rock  are  quite  marked,  in  this  respect  resembling  the  New  York 
forms  described  by  Prof.  H.  S.  Williams  (Amer.  Jour.  Sci.,  vol.  xxv,  p.  97, 
1883)  and  the  English  type  illustrated  by  Mr.  Davidson  more  than  the  Iowa 
form  of  Mr.  Calvin,  although  medium-sized  specimens  appear  to  be  per- 
fectly identical  with  the  latter. 

The  plications  on  the  valves  vary  from  eight  to  ten  on  some  examples 
and  four  to  six  on  others.  In  the  young  and  medium-sized  shells  the  plica- 
tions do  not  extend  more  than  one-half  the  way  up  from  the  anterior  margin, 
while  in  the  larger  examples  they  reach  nearly  to  the  extremity  of  the  beak. 

Under  the  name  of  Ehynchonella  Missouriensis  Shumard,  Mr.  Meek,  loc. 
cit.,  describes  and  illustrates  a  shell  which  he  considered  as  closely  allied  to 
varieties  of  Rhynchonella  reniformis  and  E.  pugnus,  from  the  Carboniferous 
limestone  of  England  and  Ireland.  This  type  was  what  Dr.  Shumard  con- 
sidered as  the  young  of  R.  Missouriensis,  describing  and  illustrating  at  the 
same  time  a  larger  shell  generically  distinct  from  it,  if  we  consider  his  fig- 
ure, 5  a  (2d  Ann.  Rep.  Geol.  Surv.  Missouri,  plate  C),  as  a  form  of  R.  pugnus, 
as  suggested  by  Mr.  Meek.  Later,  in  vol.  iii  of  the  Illinois  Survey,  Mr.  Meek 
describes  and  illustrates  the  larger  shell  described  by  Dr.  Shumard,  and  again 
speaks  of  the  relations  between  the  smaller  shell  figured  by  Dr.  Shumard 
and  R.  pugnus,  retaining  the  name  R.  Missouriensis  for  the  former  if  the 
latter  proved  to  be  identical  with  R.  pugnus. 

In  the  collections  of  the  American  Museum  of  Natural  History,  Prof. 
R.  P.  Whitfield  showed  me  casts  of  Shumard's  R.  Missouriensis  that  prove 
it  to  belong  to  the  genus  Camarophoria  as  determined  by  him. 


FOSSILS  OF  THE  DEVONIAN. 


157 


Formation  and  locality. — Devonian  limestone;  associated  with  R.  dupli- 
cata  and  R.  (L.)  Laura.  The  Gate,  northwest  of  Eureka,  Eureka  District, 
Nevada. 

Rhyiichouella  Emmonsi  U.  &  W. 

Rhynclionella  Emmonti  Hall  &  Whitfield,  1877.    Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  247, 

pi.  iii,  figs.  4-8. 

intermedia  Barris,  1878.    Proc.  Davenport  Acad.  Nat.  Sci.,  vol.  ii,  p.  285, 
pi.  xi,  figs.  5-6. 

With  the  type  of  Rhynchonella  Emmonsi  before  me,  and  a  typical  speci- 
men of  Rhynchonella  intermedia,  received  from  Rev.  W.  H.  Barris,  to  compare 
with  it,  I  fail  to  observe  any  specific  differences  between  them.  The  slight 
differences  mentioned  by  the  author  of  R.  intermedia  would  not  serve  to 
separate  the  two  shells,  if  found  in  the  same  stratum  of  rock,  and  the  range 
of  variation  in  most  species  of  the  genus  Ehynchonella  is  far  greater  than 
between  the  two  shells  under  consideration.  R.  Emmomi  is  a  rare  form  in 
the  Upper  Devonian  of  the  White  Pine  District,  Nevada,  and  Rev.  Mr.  Barris 
writes  me  that  it  is  also  rarely  met  with  in  the  Upper  Devonian  of  Iowa. 

There  is  little  doubt  but  that  Rhynchonella  intermedia,  R.  Emmonsi,  and 
R.  venustula  Hall  are  varieties  of  R.  cuboides  of  the  Devonian  of  Europe, 
and  when  the  opportunity  offers  to  illustrate  a  series  of  specimens  I  think 
this  can  readily  be  shown. 

•/ 

Many  American  species  now  under  local  names  will  ultimately  be 
placed  with  species  described  from  Europe,  and  the  reverse  will  also  be  true 
when  American  species  have  priority.  Our  knowledge  of  the  widespread 
geographic  distribution  of  paleozoic  species  will  be  greatly  increased  with 
better  facilities  for  the  comparison  of  specific  forms  from  the  great  conti- 
nental areas  and  islands. 


Subgenus  LEIOBHYNCHUS  Hall. 

Rhynchonella  (Leiorhynchus)  Nevadensis,  n.  sp. 
Plate  xiv,  figs.  9,  9  a,  1>. 

Shell  ovate  or  suborbicular,  usually  broader  than  long,  or  length  and 
breadth  subequal;  increases  in  rotundity  with  growth. 

Ventral  valve  in  adult  individuals  gibbous  above,  curving  uniformly 


158  PALEONTOLOGY  OF  THE  EUBEKA  DISTRICT. 

to  the  sides  or  becoming  slightly  depressed,  flattened  below  the  center,  and 
more  or  less  sinuate  on  the  lower  part.  Beak  acute  and  closely  incurved 
over  that  of  the  opposite  valve.  Dorsal  valve  uniformly  convex,  the  con- 
vexity increasing  with  the  size  of  the  individual ;  a  broad,  hardly  percep- 
tible mesial  fold  is  seen  on  the  lower  part  of  the  valve  only  in  the  larger 
shells. 

Surface  marked  by  a  few  obscure  plications  on  the  mesial  fold  and  in 
the  sinus  that  become  obsolete  midway  to  the  apex.  On  the  surface  of 
well-preserved  specimens  concentric  striss  occur  which  at  intervals  are 
crowded  together,  forming  slight  ridges. 

There  is  considerable  variation  between  young  and  adult  specimens. 
Those  15mm  in  length  show  but  a  trace  of  the  mesial  fold  and  sinus  or  of 
the  surface  plications;  the  ventral  valve  is  more  uniformly  convex,  less  de- 
pressed below,  and  subequal  to  that  of  the  dorsal  valve.  In  this  condition 
it  bears  a  close  resemblance  to  the  young  shells  of  some  of  the  larger  forms 
of  the  genus  Meristella. 

This  species  is  closely  related  to  R  (£.)  Kelloggi  Hall  (Pal.  N.  Y.,  vol. 
iv,  p.  .'^61,  pi.  Ivii,  figs.  1—12)  of  the  Chemung  Group  of  New  York,  the  char- 
acter of  the  mesial  fold  and  sinus  and  the  surface  plications  serving  to  dis- 
tinguish it  from  that  species. 

Formation  and  locality — Devonian  limestone.  Rescue  Hill,  near  Rescue 
Cafion,  Eureka  District,  Nevada. 

Rhynchonella  (Leiorhynchus)  slnuatua  Hall. 

Plate  xiv,  fig.  5. 
Leiorhynchus  sinuatus  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  362,  pi.  Ivii,  figs.  13-17. 

The  specimens  of  this  species  from  the  Chemung  Group  of  New  York 
are  all  more  or  less  compressed,  and  none  show  the  true  convexity  of  the 
shell  and  surface  plications.  With  this  in  view,  the  perfect  and  uncom- 
pressed specimens  from  the  limestone  of  the  Eureka  District  are  specifically 
identical  with  them.  There  is  considerable  variation  among  the  specimens 
from  the  same  bed;  some  are  more  elongate  than  the  New  York  forms, 
•while  others  are  almost  a  counterpart  of  them. 


FOSSILS  OF  THE  DEVONIAN.  159 

Formation  and  localities. — Upper  horizon  of  the  Devonian  limestone; 
The  Gate,  northwest  of  Eureka,  Rescue  Hill,  and  near  the  mouth  of  Packer 
Basin,  Eureka  District,  Nevada. 


Rhynchonella  (Leiorhynchus)  Laura  Billings. 

Rhynchonella  ?  Laura  Billings,  May,  I860.    Canadian  Journal,  vol.  v,  p.  273,  figs.  26-28. 
Leiorhynchus  multicosta  Hall,  December,  I860.    Thirteenth  Ann.  Eep.  N.  Y.  State  Cab. 

Nat.  Hist,  p.  85. 

Rhynchonella  ?  Laura  Billings,  1863.     Geol.  of  Canada,  p.  384,  figs.  418  a-c. 
Leiorhynchus  multicosta  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  358,  pi.  Ivi,  figs.  26-40. 

The  Nevada  examples  of  this  species  are  usually  broader,  more  convex, 
and  with  stronger  plications  than  those  from  the  argillaceous  shales  of  the 
Hamilton  Group  of  New  York.  These  features,  however,  are  quite  as 
prominent  in  the  specimens  from  the  arenaceous  beds  at  Richmondville, 
Schoharie  County,  New  York,  and  the  calcareous  shales  at  Bosanquet  and 
Widder,  Canada  West.  The  latter  localities  afford  specimens  showing  the 
phases  of  development  observed  in  the  New  York  and  Nevada  examples, 
and  show  the  specific  connection  of  the  eastern  and  western  forms. 

Formation  and  locality. — Upper  horizon  of  the  Devonian  limestone; 
associated  with  Rliynchonella  pugnus,  at  The  Gate,  northwest  of  Eureka, 
Nevada. 

Genus  PENTAMEEUS  Sowerby. 
Subgenus  GYPIDTJLA  Hall. 

Fentamerus  comis  Owen. 
Plate  iii,  figs.  4  and  7;  pi.  xiv,  figs.  15,  15  a,  &;  pi.  xv,  figs.  5,  5  a,  &. 

Atrypa  comis  Owen,  1852.    Eep.  Geol.  Surv.  Wis.,  Iowa,  and  Minn.,  p.  583,  pi.  iii  A, 

fig.  4. 
Pentamerus  occidentalis  Hall,  1858.     Geol.  Iowa,  vol.  i,  pt.  2,  p.  514,  pi.  vi,  figs.  2  a-c. 

Not  Pentamerus  occidentalis  Hall,  1852,  Pal.  N.  Y.,  vol.  ii,  p.  341,  pi.  Ixxix, 

figs.  1  a-s,  2. 
Pentamerus  galcatiform  Meek  &  Worthen,  1866.    Geol.  Surv.  Illinois,  vol.  ii,  p.  325, 

(foot  note.) 

Oypidula  occidentalis  Hall,  1867.    Pal.  N.  Y.,  vol.  iv,  p.  380,  pi.  Iviii  a,  figs.  1-8. 
Pentamerus  comis  Meek  &  Wortheu,  1868.    Geol.  Surv.  Illinois,  vol.  iii,  p.  428,  pi, 

xiii,  figs.  6  a-c. 


160  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Shell  ovoid  or  subglobose;  very  inequi valve;  hinge  line  varying  from 
two-thirds  to  three-fourths  of  the  entire  width  of  the  shell. 

Ventral  valve  arcuate,  much  deeper  than  the  dorsal,  gibbous  or  regu- 
larly ventricose  above  the  middle ;  beak  strongly  incurved  over  that  of  the 
opposite  valve;  fissure  of  medium  size,  and  bordered  by  a  more  or  less  dis- 
tinct area,  the  surface  of  which  is  smooth  or  transversely  striated.  The 
spoon-shaped  pit  in  the  interior  of  the  valve  is  moderately  extended; 
median  septum  very  short.  Central  portion  of  the  valve  with  a  slightly 
elevated,  broad,  more  or  less  distinctly  defined  mesial  fold. 

Dorsal  valve  full  above,  becoming  depressed  below  the  middle  and 
flattened  at  the  sides;  the  front  is  flattened  and  slightly  extended,  forming 
a  broad,  more  or  less  distinct  sinus.  Lamellae-  separate  and  diverging. 

Surface  obscurely  plicated  on  the  lower  central  portion  of  the  larger 
shells,  and  one  shows  traces  of  very  fine  radiating  striae  on  the  lower  part  of 
the  ventral  valve. 

The  specimen  described  is  smaller  than  the  average,  having  a  height 
and  width  of  35mm,  with  the  diameter  of  the  convexity  of  the  valves  of 
SO*"";  a  large  ventral  valve  is  50mm  in  length. 

Formation  and  localities. — Devonian  limestone,  lower  horizon;  Comb's 
Peak,  Eureka  District,  and  Lone  Mountain,  18  miles  northwest  of  Eureka, 
Nevada. 

The  most  striking  differences  between  the  Nevada  shell  and  that  of 
Iowa  is  the  great  size  and  the  almost  entire  absence  of  plications  on  the 
former.  We  cannot,  however,  avoid  the  conclusion  that  they  belong  to 
the  same  species,  the  Nevada  form  attaining  a  greater  size  and  in  many 
instances  a  broader  form.  In  other  examples  the  specific  identity  is  without 
question. 

When  preparing  specimens  for  the  draughtsman  it  was  thought  that  figs. 
15,  15  a,  &,  plate  xiv,  represented  one  species,  figs.  5,  5  a,  b  another,  and  Pen- 
tamerus  occidentalis  Hall,  loc.  cit.,  still  another. 

By  the  collection  of  a  large  series  of  specimens  from  the  original 
locality  in  Nevada,  and  the  bringing  together  of  a  fine  suit  of  specimens 
representing  the  Devonian  P.  occidentalis  Hall  (the  latter  through  the  kind- 
ness of  Prof.  Samuel  Calvin  and  Rev.  William  H.  Barris,  of  Iowa),  I 


FOSSILS  OF  THE  DEVONIAN. 


161 


found  that  the  three  varieties  were  united  by  a  series  of  specimens  having 
intermediate  characters  between  the  extremes  I  had  designated  as  distinct 
species.  On- examining  the  interiors  of  the  valves  of  the  Iowa  and  Nevada 
shells,  they  were  found  to  be  similar;  also  the  area,  which  is  of  a  variable 
character.  In  a  beautiful  series  of  specimens  from  Independence,  Iowa, 
received  from  Professor  Calvin,  the  area  of  the  ventral  valve  varies  greatly 
in  extent  and  height,  and  many  of  them  showed  no  more  of  a  decided  area 
than  specimens  of  P.  galeatus,  now  before  me,  from  the  Lower  Helderberg 
Group  of  Albany  County,  New  York.  On  one  of  Professor  Calvin's  speci- 
mens from  Solon,  Iowa,  the  area  appears  to  be  vertically  striated,  but  a  close 
examination  shows  this  to  have  originated  from  the  scratching  of  the  tool 
used  in  cleaning  away  the  matrix.  All  other  specimens  from  Iowa  and  Ne- 
vada showing  the  area  intact,  are  transversely  striated.  When  the  area  is 
not  well  defined  the  striae  of  growth  arch  around  the  rounded  lateral  margins 
and  reach  in  to  the  edges  of  the  vertical  fissure.  Professor  Hall  describes 
the  area  as  vertically  striated;  we  have  failed  to  find  any  specimens  showing 
the  vertical  striae.  The  presence  of  fine  radiating  striae  is  not  mentioned 
either  by  Owen,  Hall,  or  Meek  and  Worthen,  but  they  are  present  on  speci- 
mens from  Davenport,  Troy  Mills,  and  Independence,  Iowa,  and  the  Eureka 
District,  Nevada.  Concentric  striae  are  also  well  defined  on  many  speci- 
mens, while  others  show  little  more  than  a  smooth  surface. 

I  think  the  identification  of  this  species  by  Meek  and  Worthen  with  that 
of  Owen  is  correct,  and  it  also  establishes  a  specific  name,  as  the  genus  Gyp- 
idula  Hall,  does  not  appear  to  have  good  generic  characters  to  distinguish 
it  from  typical  forms  of  Pentamerus,  and  if  the  species  is  referred  back  to 
the  latter  genus,  the  name  occidentalis  cannot  be  used  owing  to  its  being  pre- 
occupied. 

Pentamerus  Lotis,  n.  sp. 
Plate  iii,  figs.  9, 9a-c. 

Shell  small,  subglobose,  transverse  or  with  the  height  and  width  sub- 
equal. 

Dorsal  valve  deeper  and  more  convex  than  the  ventral;  regularly 
arched  from  beak  to  front,  with  a  strongly  marked  somewhat  flattened  me- 
11  o  D  w 


162  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

sial  fold  having  a  shallow  median  sinus;  beak  short,  incurved.  Ventral 
valve  most  convex  towards  the  beak,  flattening  out  in  the  broad  mesial  sinus; 
the  latter  is  marked  by  a  low  rounded  median  plication. 

Surface  of  dorsal  valve  marked  by  a  single  low  plication  on  each  side 
of  the  mesial  fold  that  corresponds  to  a  shallow  sinus  each  side  of  the  pli- 
cation bordering  the  large  mesial  sinus  of  the  ventral  valve;  a  few  fine  con- 
centric lines  of  growth  are  visible  by  the  aid  of  a  strong  lens. 

Dimensions:  height  of  largest  specimen  in  the  collection,  9mm;  width, 
12mm;  convexity  of  the  two  valves  united,  8mm. 

On  a  shell  having  a  height  of  4mm,  a  transverse  diameter  of  5mm,  and  a 
depth  of  2.25mm  for  the  two  valves,  the  mesial  sinus  and  fold  are  shown  only 
by  an  undulation  in  the  front  margin,  the  valves  are  subeqtial  in  convexity 
and  the  beak  of  the  dorsal  valve  is  scarcely  elevated  above  that  of  the  ven- 
tral. With  the  increase  in  the  size  of  the  shell,  the  features  of  the  adult 
gradually  appear  until,  in  the  largest  specimens,  there  is  very  little  variation 
in  form  except  a  greater  or  less  convexity  as  the  shell  is  more  or  less  trans- 
verse. 

Of  American  species  Pentamerus  subgldbosus  M.  &  H.  (Geol.  Illinois,  vol. 
iii,  p.  429,  plate  xiii,  figs.  5  a-c),  approaches  this  species  in  size  and  form,  but 
the  numerous  plications  and  different  convexity  of  the  valves  distinguish 
them.  Pentamerus  Hplicatus  Schnur,  of  the  Middle  Devonian  of  England 
(Davidson,  Mon.  Brit.  Foss.  Brach.,  vol.  iii,  p.  73),  may  also  be  compared 
with  P.  Lotis. 

It  is  with  considerable  hesitancy  that  this  Upper  Devonian  shell  is 
referred  to  a  new  species,  as  it  may  possibly  be  a  form  descended  from  P. 
comis,  of  the  Lower  Devonian  of  the  Eureka  District.  No  young  shells  of 
the  latter  species  have  been  found  that  we  can  compare  with  the  earlier 
stages  of  growth  of  P.  Lotis,  but  in  the  larger  form  of  the  two  species  de- 
cided differences  appear,  as  may  be  seen  by  a  comparison  of  the  figures 
representing  them. 

Comparing  P.  Lotis  with  smooth  specimens  of  P.  comis,  from  the  Upper 
Devonian  horizon  at  Rockford,  Iowa,  we  find  a  decided  resemblance  between 
them,  but  not  sufficient  to  unite  them  as  one  species. 

Formation  and  locality. — Upper  Devonian,  on  the  west  side  of  Apple- 
gate  Canon,  White  Pine  Mining  District,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


163 


Genus  CRYPTONELLA  Hall. 

Cryptonella  ?  circula,  n.  sp. 

Plate  xv,  figs.  2,  2  a,  6. 

Shell  small,  subcircular  or  ovoid.  The  depth  of  the  two  valves,  in 
uncompressed  specimens,  is  equal  to  one-half  the  length  of  the  shell. 

Ventral  valve  moderately  convex,  most  prominent  about  one-third  the 
distance  from  the  apex  to  the  front,  from  which  point  it  slopes  regularly  to 
the  margins  and  beak;  a  slight  depression  of  the  front  margin  is  the  only 
indication  of  a  mesial  sinus;  beak  scarcely  incurved,  truncated  by  a  small 
round  foramen,  that,  in  the  absence  of  the  deltidial  plates,  opens  below  into 
a  rather  large  deltoid  fissure  that  has  a  narrow,  flattened,  area-like  space  on 
each  side.  Dorsal  valve  somewhat  shorter  than  the  ventral  and  subequal 
in  convexity  with  it.  Beak  very  small  and  not  perceptibly  incurved. 

Surface  marked  by  fine  concentric  striae.     Shell  structure  punctate. 

Dimensions:  the  largest  shell,  in  a  collection  of  thirty  specimens,  has 
a  length  of  9mm,  breadth  of  8.5mm,  and  depth  of  the  two  valves  of  4.5mm. 

The  species  is  referred  to  the  genus  Cryptonella,  from  its  general  form, 
the  character  of  the  beak  of  the  ventral  valve  and  the  punctate  shell  struc- 
ture, the  latter  character  shown  on  one  of  the  silicified  specimens.  With 
these  characters  the  reference  is  provisional,  as  the  internal  features  are  yet 
undetermined. 

Formation  and  locality. — Devonian  limestone ;  Lone  Mountain,  1 8  miles 
northwest  of  Eureka,  Nevada. 


Cryptonella  Pinonensis,  n.  sp. 
Plate  iv,  figs.  4,  4  a,  6. 

Shell  subovate;  widest  about  the  middle;  valves  about  equally  convex; 
rounded  to  slightly  transverse  in  front. 

Ventral  valve  regularly  arcuate,  most  convex  midway;  beak  elevated, 
slightly  incurved,  and  truncated  by  a  small  rounded  foramen  bounded  on  the 
lower  side  by  two  rather  prominent  deltidial  pieces;  the  slopes  from  the  beak 
are  abruptly  deflected  on  the  sides  down  to  the  cardinal  margin. 


164  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

Dorsal  valve  not  quite  as  convex  as  the  ventral;  most  elevated  at  the 
center,  from  which  point  it  curves  regularly  to  the  margins;  beak  incurved 
beneath  the  deltidial  plates  of  the  ventral  valve. 

Outer  surface  exfoliated.     Shell  structure  punctate. 

The  generic  reference  is  based  entirely  on  external  form  and  character; 
nothing  is  known  of  the  interior  characters,  except  two  elongate,  median, 
muscular  imprints  on  the  ventral  valve.  The  specific  relations  appear  to  be 
nearest  some  forms  of  Cryptonella  planirostra  of  the  Hamilton  Group  of  New 
York.  A  direct  comparison  with  the  types  of  that  species,  and  also  of  C. 
rectirostra  Hall,  leads  us  to  think  that  the  Nevada  form  is  distinct  from  each, 

Formation  and  locality. — Upper  Devonian;  south  end  of  the  Pinon 
Range  at  The  Gate,  northwest  of  Eureka,  Nevada. 


LAMELLIBRANCHIATA. 

Our  knowledge  of  this  class  of  shells  in  the  Devonian  Group  of  the 
area  embraced  within  the  Rocky  Mountains  has  been  up  to  the  present  time 
very  limited,  Mr.  Meek  having  described  but  three  species,  viz,  Edmondia  f 
Pinonensis,  Aviculopecten  catactus,  and  Lunulicardium  fragosum,  the  types  of 
which  were  collected  by  the  geologists  of  the  Fortieth  Parallel  Geological 
Survey,  in  Central  Nevada.  To  this  list  we  have  added  twenty-three  genera, 
represented  by  thirty-five  species.  Of  these,  eight  species  are  identical 
with  species  in  the  Eastern  Paleozoic  area  of  Ohio  and  New  York,  viz: 

Actmopteria  Boydi. 
Paracyclas  occidentals. 
Pteriuea  flabella. 
Leiopteria  Eafinesqui. 
San  gum  elites  rigidus. 
Sanguinolites  ?  Sanduskyensis. 
Sanguinolites  ventricosus. 

All  of  the  twenty-three  genera,  with  the  exception  of  Posidonomya, 
are  identical  with  Devonian  genera  of  the  Eastern  United  States. 

In  the  systematic  catalogue  at  the  end  of  this  volume  the  vertical  range 
of  the  various  species  in  the  Devonian  Group  of  the  Eureka  District  is 
given. 


FOSSILS  OF  THE  DEVONIAN.. 


165 


From  the  results  obtained  by  a  few  days'  collecting  at  the  Lower 
Devonian  horizon,  there  is  little  doubt  but  that  by  a  more  extended  search 
the  number  of  species  could  be  greatly  increased  over  the  twenty-seven 
now  known  from  that  horizon. 

One  species,  Paracyclas  occidentalis,  passes  from  the  lower  to  the  upper 
horizon,  and  unites  with  the  eight  species  occurring  there  to  make  a  total 
of  nine  species  occurring  in  a  horizon  stratigraphically  equivalent  to  that  of 
the  Chemung  Group  of  New  York. 

Genus  PTERINEA  Goldfuss. 

Pterinea  flabella  Conrad  (Sp.). 
Plate  xv,  fig.  12;  pi.  v,  fig.  6. 

Avicula  flabella  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p.  238,  pi.  12,  fig. 8. 
Pterinea  flabellum  Hall  &  Whitfield,  1872.     Twenty-fourth  Ann.  Kep.  N.  T.  State 

Museum  Nat.  Hist.,  p.  199. 
Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations,  p.  7j 

pi.  xiv,  figs.  1-21 ;  pi.  xv,  figs.  1, 4, 5,  8-10.    Ibid.,  1884,  Text,  p.  93. 

This  species,  which  in  Ohio  and  New  York  ranges  from  the  Upper 
Helderberg  to  the  Chemung  Groups,  is  found  only  at  the  Lower  Devonian 
horizon  of  Lone  Mountain,  18  miles  northwest  of  Eureka,  Nevada. 

The  specimen  illustrated  shows  the  characteristic  form,  and  is  similar 
to  that  from  the  typical  localities  in  the  Hamilton  Group  of  New  York. 


Pterinea  Newarkensis,  n.  sp. 
Plate  v,  fig.  12. 

General  form  broadly  truncate,  suboval;  length  and  breadth  subequal; 
cardinal  margin  straight,  nearly  if  not  quite  equaling  the  greatest  width  of 
the  valves. 

The  right  valve  is  depressed,  slightly  convex  at  the  umbonal  region; 
beak  depressed;  anterior  surface  of  posterior  wing  marked  by  a  few  linear, 
radiating  lines,  the  body  of  the  shell  showing  only  a  few  concentric  lines 
of  growth.  The  posterior  muscular  scar  is  oval  in  form  and  quite  shallow. 


166  PALEONTOLOGY  OF  THE  ETJEEKA  DISTRICT. 

Left  valve  unknown. 

Dimensions :  length  of  shell,  4.5cm;  width  the  same. 

This  species  is  closely  related  to  Pterinea  Chemungensis  Conrad  (PaL 
N.  Y.,  vol.  v,  pt.  1,  p.  98,  1884)  from  the  Devonian  of  New  York.  It  differs 
in  the  more  anterior  position  of  the  beak  and  less  elongate  outline. 

Formation  and  locality. — Upper  Devonian  of  Newark  Mountain,  Eureka 
District,  Nevada. 

Genus  ACTINOPTERIA  Hall. 

Actinopteria  Boydi  Conrad  (Sp.). 
Plate  v,  fig.  2. 

Avicula Boydii  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p.  237,  pi.  xii,  fig. 4. 

Pterinea  Boydi  Miller,  1877.    Cat.  Amer.  Pal.  Fossils,  2d  ed.,  p.  201. 

Actinoptera  Boydi  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations,  p.  8; 

pi.  xix,  figs.  2-24. 
Actinopteria  Boydi  Hall,  1884.    Pal.  N.  Y.,  vol.  v,  pt.  1,  p.  113. 

There  is  only  a  single  left  valve  of  this  species  in  the  collection,  and 
that  is  somewhat  distorted  by  pressure.  A  direct  comparison  with  authentic 
specimens  from  the  Hamilton  Group  of  New  York  shows  such  a  striking 
similarity  between  them  and  the  Nevada  shell  that  there  is  little  hesitancy 
in  identifying  the  species  by  the  one  specimen. 

Formation  and  locality. — Lower  Devonian  of  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 

Genus  LEIOPTEKIA  Hall. 

Leiopteria  Rafinesquii  Hall. 
Plate  v,  figs.  10,  10  a. 

Leiopteria  Bqfinesquii  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations,  pp. 
7,  9;  pi.  xv,  fig.  11;  pi.  xx,  figs.  6,  7.     Ibid.,  1884,  text,  p.  161. 

The  examples  of  this  species  from  Nevada  embrace  both  the  Upper 
Helderberg  and  Hamilton  Group  forms,  as  illustrated  in  the  Paleontology 
of  New  York.  The  identification  is  made  with  the  figures,  as  we  have  no 
typical  specimens  of  the  species  for  comparison. 

Formation  and  locality. — Lower  Devonian  of  Brush  Peak  and  Atrypa 
Peak,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


167 


Genus  LEPTODESMA  Hall. 

Leptodesma  traiisversa,  n.  sp. 
Plate  v,  fig.  13. 

General  form  transversely  ovate  or  oblong.  General  surface  of  the 
left  valve  strongly  convex,  but  not  gibbose.  Hinge  straight  and  continued 
posteriorly  to  the  acute  termination  of  the  wing,  which  appears  to  have  had 
a  short  spinose  extension.  Beaks  small,  arching  over  the  cardinal  line. 

Surface  marked  by  numerous  concentric  lines  of  growth. 

Interior  characters  unknown. 

Dimensions:  height,  7mm;  breadth,  12mm;  convexity  of  left  valve,  2.5 mm. 

With  the  exception  of  Leptodesma  naviforme  Hall  (Pal.  N.  Y.,  vol.  v, 
pt.  1,  p.  200),  of  the  Chemung  Group  of  New  York,  this  species  is  more 
oblique  and  transverse  than  any  species  known  to  me. 

Formation  and  locality. — Upper  Devonian,  Chemung  horizon,  at  The 
Gate,  northwest  of  Eureka,  Nevada. 


Genus  LIMOPTERA  Hall. 

Limoptera  sarmenticia,  D.  sp. 
Plate  v,  figs.  3, 3  a,  b. 

Shell  oblique,  subovate  in  outline  within  the  extension  of  the  posterior 
wing.  Left  valve  strongly  convex.  Hinge-line  straight ;  ligamental  area 
unknown.  Beak  of  left  valve  elevated  and  incurved  over  the  cardinal  line. 

Surface  marked  by  concentric  lines  of  growth,  and  not  very  strong 
radiating  striae. 

Interior  characters  unknown. 

Dimensions:  height  of  a  narrow  specimen,  3.25cm;  breadth,  2.5cm;  con- 
vexity of  left  valve,  1.25cm;  of  a  broad  specimen:  height,  3cm;  breadth,  3cm; 
convexity  of  left  valve,  1.25cm. 

This  is  unlike  any  species  of  the  genus  known  to  me.  The  variation 
in  form  among  the  different  specimens  is  considerable,  as  is  shown  by  figs. 
3  a  and  3 1).  The  surface  striae  are  usually  absent  in  the  cast. 


168  PALEONTOLOGY  OF  THI   EUBEKA  DISTRICT. 

The  specific  name  is  given  from  the  character  of  the  localities  at  which 
it  occurs;  both  Brush  and  Atrypa  Peaks  are  covered  with  brushwood. 

Another  strongly  marked  species  of  Limoptera  occurs  in  the  Lower 
Devonian.  It  is  much  larger  and  more  erect  than  the  species  under  con- 
sideration. Unfortunately,  the  material  does  not  permit  of  specific  deter- 
mination. 

Formation  and  locality. — Lower  Devonian  of  Brush  and  Atrypa  Peaks, 
Eureka  District,  Nevada. 

Genus  MYTILAKCA  HalL 

Mytilarca  dubia,  n.  sp. 
Plate  iv,  fig.  5. 

General  outline  broadly  ovate.  Hinge-line  short,  projecting  a  short 
distance  beyond  the  contour  of  the  body  of  the  shell. 

Left  valve  unknown.  The  beak  of  the  right  valve  is  somewhat  acute 
and  projects  over  and  above  the  hinge  line;  area  unknown.  General  sur- 
face strongly  convex.  Surface  of  valve  apparently  smooth. 

Dimensions:  length,  4.25cm;  greatest  breadth,  3.75°"*. 

In  the  absence  of  the  ligamental  area  and  the  interior  of  the  valves, 
this  species  is  provisionally  referred  to  the  genus  Mytilarca.  In  general 
form  it  is  related  to  Mytilarca  (Plethomytilus)  oviformis  (p.  169)  of  the  Hamil- 
ton Group  of  New  York. 

Formation  and  locality. — Lower  Devonian,  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 

Mytilarca  Chemuiigensis  Conrad. 
Plate  iv,  fig.  9. 

Inoceramus  Cliemungensis  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.,  PMlad.,  vol.  viii,  p. 

246,  pi.  xiii,  fig.  9. 
Mytilm  Chemungensis  Phillips  &  Salter,  1848.    Memoirs  Geol.  Surv.  of  Great  Britain, 

vol.  ii,  pt.  1,  p.  365,  pi.  xx,  figs.  10,  11.     (This  is  probably  a  distinct  species.) 
Mytilarca  Chemungensis  Hall,  1870.     Prelim.  Notice  Lam.  Shells,  p.  23.    Ibid.,  1883. 

Pal.  N.  Y.,  vol.  v,  pt.  1 ;  Plates  and  Explanations,  p.  11 ;  pi.  xxxii, 

8-14.    Ibid.,  1884.    Text,  p.  258. 


FOSSILS  OF  THE  DEVONIAN. 


169 


As  far  as  can  be  determined  by  a  comparison  of  the  single  right  valve 
that  we  have  of  this  species  with  specimens,  and  also  Professor  Hall's  figures, 
it  is  identical  with  the  New  York  species.  It  occurs  in  association  with  the 
following  Chemung  species :  Orthis  impressa,  Productus  speciosus,  P.  lacliry- 
mosa,  vars.  lima  and  stigmata,  Spirifera  disjuncta,  Atliyris  Angelica,  Ehyncho- 
nella  sinuata,  Sanguinolites  rigidus. 

Formation  and  locality. -r-Upper  Devonian,  at  The  Gate,  northwest  of 
Eureka,  Nevada. 

Subgenus  PLETIIOMYTILTTS  Hall. 

Mytilarca  (Pie thorny tilns)  oviformis  Conrad. 
Plate  v,  fig.  11. 

Inoceramus  oviformis  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.,  Philad.,  vol.  viii,  p.  246, 

pi.  xiii,  fig.  7. 

Mytilarca  oviformis  Hall,  1870.    Prelim.  Notice  Lam..  Shells,  p.  21. 
Plethomytilus  oviformis  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1;  Plates  and  Explanations, 

p.  11;  pi.  xxxi,  figs.  1-8. 
Mytilarca  (Plethomytilus)  oviformis  Hall,  1884.    Pal.  N.  Y.,  vol.  v,  pt.  1,  p.  255;  pL 

Ixxxvii,  fig.  8. 

But  a  single  left  valve  of  this  species  has  been  obtained.  In  form  and 
external  characters  it  corresponds  too  closely  with  M.  (P.)  oviformis  of  the 
Hamilton  Group  of  New  York  to  admit  of  a  specific  separation.  It  may  be 
that  if  the  ligamental  area  and  hinge  were  known,  differences  of  generic 
value  would  appear,  but  with  the  present  knowledge  of  the  shell  this  is  not 
anticipated. 

Formation  and  locality. — Lower  Devonian,  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


Genus  MODIOMOEPHA  Hall. 

Modiomorpha  altiforme,  n.  sp. 
Plate  v,  fig.  9. 

Shell  transverse,  suboval  to  subquadrangular  in  outline.     General  sur- 
face strongly  convex,  with  the  umbonal  ridge  prominent. 


170  PALEONTOLOGY  OF  THE  EUKEKA  DIS1EICT. 

Valves  with  small  incurved  beaks  situated  well  towards  the  anterior 
end  of  the  nearly  straight  cardinal  line. 

Surface,  as  shown  by  the  impression  left  in  the  cast,  marked  by  con- 
centric lines  of  growth. 

Dimensions:  height,  4cm;  breadth,  6. 5cm;  convexity  of  right  valve,  17mm. 

Four  specimens  of  this  species  have  been  obtained,  all  in  the  form  of 
casts.  The  transverse  subquadrangular  form  serves  to  distinguish  it  from 
Modiomorpha  alia  of  the  Hamilton  Group  of  New  York,  which  is  the  most 
nearl}^  allied  species.  Some  specimens  that  are  referred  to  M.  alia  are 
almost  identical  in  form,  but  the  typical  forms  differ  materially,  as  may  be 
seen  by  comparing  our  figure  with  those  given  of  the  New  York  species 
(Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations,  pi.  xxxvii). 

Formation  and  locality. — Lower  Devonian ;  Lone  Mountain,  1 8  miles 
northwest  of  Eureka,  Nevada. 


Modiomorpha  oblonga,  n.  sp. 
Plate  v,  fig.  7. 

Shell  transversely  elliptical  or  elongate-ovate.  General  surface  mod- 
erately convex,  with  a  distinct,  rounded  umbonal  ridge. 

Hinge-line  shorter  than  the  length  of  the  shell  and  nearly  straight. 
Beaks  anterior,  small,  and  incurved.  Surface  marked  by  concentric  lines 
of  growth. 

Dimensions:  height,  2.75cna;  breadth,  5.5cm;  convexity  of  left  valve, 
0.75^. 

This  species  is  more  nearly  related  to  Sanguinolites  ?  Sanduskyensis  Meek 
(Pal.  Ohio,  vol  1,  p.  209,  pi.  xviii,  fig.  3),  from  the  Helderberg  Group  of 
Ohio,  than  to  any  other  species  with  which  we  are  acquainted.  It  is  less 
expanded  posteriorly,  and  the  anterior  extremity  is  not  as  uasute.  The 
generic  reference  is  made  on  the  general  form,  as  the  hinge  characters  are 
unknown. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka 
District,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


171 


Modiomorpha  obtusa,  n.  sp. 
Plate  iv,  figs.  8,  8 a. 

Shell  subrhomboidal  in  outline.  General  surface  strongly  convex,  the 
umbonal  ridge  rounded.  Hinge-line  about  one-half  the  length  of  the  shell. 
Beaks  small,  incurved,  and  situated  on  the  anterior  third  of  the  cardinal  por- 
tion of  the  shell. 

Surface  marked  by  a  few  concentric  lines  of  growth.  Anterior  muscu- 
lar scar  large,  well  denned;  other  interior  characters  unknown. 

Dimensions-,    height,    1.5cm;   width,   2.5cm;    depth  of  right  valve,  0.5cm. 

To  some  of  the  more  transverse  forms  of  Modiomorpha  quadrula  Hall 
(Pal.  N.  Y.,  vol.  v,  pt.  2,  Plates  and  Explanations,  pi.  xli,  figs.  18-26), 
this  species  bears  a  stronger  resemblance  than  to  any  other  form  we  know. 
It  differs  in  the  character  of  the  umbonal  ridge  and  the  posterior  extension 
of  the  shell. 

Formation  and  locality. — Lower  Devonian  of  Brush  Peak,  Eureka  Dis- 
trict, Nevada,  and  also  at  the  same  horizon  on  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


Genus  GONIOPHOBA  Phillips. 

Goniophora  peraugulata  H. 

Plate  xv,  fig.  10. 

Sanguinolites  perangulatus  Hall,  1870.    Prelim.  Notice  Lam.  Shells,  p.  35. 
Goniophora  perangulata  Hall,  1883.     Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations, 
p.  12,  pi.  xxxiv,  figs.  1-7. 

In  identifying  this  species  a  direct  comparison  was  made  between  the 
specimens  from  Nevada  and  the  type  specimens  from  the  Upper  Helder- 
berg  Group  of  New  York,  at  the  New  York  State  Museum  of  Natural  His- 
tory, Albany,  N.  Y.  No  variations  of  specific  value  were  observed;  the 
identification  is  further  strengthened  by  the  presence  of  Pterinea  fldbetta  and 
several  species  of  Brachiopods,  that  are  associated  with  the  species  at  each 
locality. 

Formation  and  locality. — Lower  Devonian;  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


172  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  NUOULA  Lamarck, 

Nucula  Rescuensis,  n.  sp. 

Plate  xv,  fig.  9. 

Shell  small,  broadly  subovate,  moderately  convex;  height  to  length 
as  four  to  five;  beaks  not  very  prominent,  about  one-fifth  the  length  from 
the  broadly  rounded  anterior  end;  basal  line  broadly  and  uniformly  curved; 
posterior  end  more  sharply  curved,  and  with  the.  upper  slope  meeting  the 
nearly  straight  hinge-line  at  an  obtuse  angle;  posterior  umbonal  slope 
prominent  and  subangular. 

Surface,  in  the  cast,  shows  evidence  of  concentric  lines  of  growth 
where  the  cast  is  very  perfect,  otherwise  it  is  smooth. 

Formation  and  locality. — Middle  to  Upper  Devonian  horizon;  Rescue 
Hill,  west  of  Rescue  Canon,  Eureka  District,  Nevada. 

Nucula,  sp.  ? 

Among  the  collections  from  Rescue  Hill  a  number  of  casts  of  a  larger 
species  of  Nucula  than  N.  Eescuensis  occur.  Their  form  is  much  like  that 
of  N.  Niotica  of  the  Upper  Helderberg  Group  of  New  York,  but  without 
some  knowledge  of  the  outer  shell  it  is  scarcely  possible  to  determine 
whether  it  is  that  species,  or  a  new  form  allied  to  some  of  the  Devonian  or 
Chemung  species  of  New  York. 

Genus  DYSTACTELLA  Hall. 

Dystactella  insularis,  n.  sp. 
Plate  xv,  fig.  8. 

Shell  transversely  elongate-ovate,  the  length  and  height  as  two  to 
one;  valves  moderately  convex;  anterior  end  contracted  and  sharply 
rounded  at  the  extremity;  basal  line  gently  arcuate;  posterior  end  some- 
what broadly  rounded,  the  extremity  coming  above  a  line  drawn  through 
the  transverse  center  of  the  shell;  cardinal  line  a  little  curved;  beaks 
depressed. 

Surface  of  cast  marked  by  a  strong  anterior  muscular  scar;  posterior 
scar  not  observed. 


FOSSILS  OF  THE  DEVONIAN. 


173 


In  general  appearance  this  shell  resembles  a  Nuculites  or  Palseoneilo, 
but  it  is  without  the  clavicular  ridge  of  the  former  and  the  faint  muscular 
scars  of  the  latter.  In  the  presence  of  the  strong  anterior  muscular  scar, 
the  somewhat  nasute  anterior  end  and  the  rounded  up  posterior  extremity 
it  is  allied  to  Dystactella  subnasuta,  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and 
Explanations,  p.  14,  pi.  li,  figs.  28-3!,  18'83)  from  the  Upper  Helderberg 
rocks  of  the  Falls  of  the  Ohio. 

Formation  and  locality. — Lower  part  of  the  Devonian  limestone  in  the 
lower  or  central  area  of  Gray's  Canon,  Eureka  District,  Nevada. 

Genus  MEGAMBONIA  HalL 

Megambonia  occidualis,  n.  sp. 
Plate  v,  fig.  1. 

Outline  subcircular.  Length  and  breadth  subequal.  General  sur- 
face strongly  convex,  with  a  convex  anterior  wing  separated  from  the 
body  of  the  shell  by  a  well-marked,  slightly  curved  sinus.  Hinge-line 
shorter  than  the  width  of  the  shell. 

Right  valve  unknown.  Left  valve  with  the  beak  depressed  and  curv- 
ing forward  over  the  cardinal  line.  Area  and  interior  characters  unknown. 

Surface  marked  by  strong  concentric  striae  and  lines  of  growth;  a  few 
radiating  lines  are  shown  in  the  posterior  half  of  the  shell. 

The  most  nearly  related  species  is  Megambonia  subcordjformis  Hall 
(Pal.  N.  Y.,  vol.  v,  pt.  1 ;  Plates  and  Explanations,  pi.  Hi,  figs.  1,  8).  The  dif- 
ferences are  the  less  elongate  form  and  the  character  of  the  surface  markings. 

Formation  and  locality. — Lower  Devonian;  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


Genus  NYASSA  Hall. 

Nyassa  parva,  n.  sp. 
Plate  xv,  figs.  14,  14  a. 

Shell  small,  transversely  elongate,  with  the  cardinal  and  basal  margins 
subparallel,  the  posterior  end  being  a  little  broader  than  the  anterior;  the 


174  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

width  about  twice  the  height;  beaks  moderately  prominent  and  incurved, 
situated  near  the  anterior  end,  which  is  rather  abruptly  rounded;  basal  line 
slightly  sinuate  midway;  posterior  end  obliquely  rounded,  truncate  above 
the  lower  third,  rounding  into  the  basal  line  and  forming  a  very  obtusely 
rounded  angle  with  the  cardinal  margin;  cardinal  line  nearly  straight  and 
declining  towards  the  anterior  end;  umbonal  ridge  prominent,  subangular, 
becoming  more  rounded  toward  the  extremity  of  the  posterior  portion  oi 
the  shell. 

Surface  showing  a  few  lines  of  growth.  Anterior  muscular  scar  small, 
semicircular,  and  near  the  anterior  margin ;  posterior  scar  subcircular,  not 
strongly  denned,  situated  on  the  postero-cardinal  slope,  near  the  margin. 

This  species  resembles  Nyassa  recta  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  1, 
Plates  and  Explanations,  p.  14,  pi.  liii,  figs.  1-8,  1883)  of  the  Hamilton 
Group  of  New  York,  but  differs  in  the  outline  of  the  valves  and  its  less 
prominent  beaks. 

Formation  and  localities. — Lower  Devonian;  on  the  west  slope  of 
County  Peak,  Middle  to  Upper  Devonian,  at  Rescue  Hill,  west  of  Rescue 
Canon,  Newark  Mountain,  and  east  side  of  Packer  Basin,  Eureka  District, 
Nevada. 

Genus  GRAMMYSIA  De  Verneuil. 

Grammy sia  minor  n.  ep. 
Plate  xv,  figs.  15,  15  o. 

Shell  very  small,  transversely  elongate-ovate;  valves  ventricose;  beaks 
strongly  incurved,  situated  near  the  anterior  end,  which  slopes  abruptly 
from  the  beak  with  a  slightly  concave  outline  to  the  somewhat  sharply 
rounded  end  that  passes  below  into  the  basal  line;  this,  with  the  exception 
of  a  slight  sinuosity  caused  by  the  median  or  byssal  groove,  is  transverse 
to  where  it  rounds  up  slightly  on  the  posterior  margin  to  meet  the  oblique 
line  of  the  upper  postero-margin,  with  which  it  forms  an  obtuse  angle, 
giving  the  posterior  end  of  the  shell  a  pointed  appearance;  cardinal  line 
straight  about  two- thirds  the  length  of  the  valve;  umbonal  ridge  rounded 
or  subangular,  postero-cardinal  slope  abrupt. 

Surface  marked  by  rather  strong,  rounded  concentric  ridges  and  fur- 
rows that  are  nearly  obsolete  on  the  posterior  umbonal  slope. 


FOSSILS  OF  THE  DEVONIAN. 


175 


Length  of  average  size  specimen,  12mm;  height,  7mm. 

This  species  is  allied  to  the  young  shells  of  Grammysia  Hannibalensis 
Shumard  (Pal.  N.  Y.,  vol.  v,  pt.  1 ,  Plates  and  Explanations,  pi.  Ixi,  figs.  23-33), 
but  in  the  more  anterior  position  of  the  beaks  and  small  size  it  differs; 
it  occurs  at  an  horizon  about  3,500  feet  lower  in  the  strata. 

Formation  and  localities. — Upper  portion  of  the  Devonian  limestone,  on 
Rescue  Hill,  west  of  Rescue  Canon,  and  also  at  The  Gate,  northwest  of 
Eureka,  Nevada. 

Genus  SANGUINOLITES  McCoy. 

Sanguinolites  ?  Combensis,  n.  sp. 

Plate  xv,  fig.  16. 

Shell  very  elongate,  the  length  being  about  four  times  the  height; 
moderately  convex.  Anterior  end  contracted  and  uniformly  rounded  on 
the  lower  portion,  about  one-sixth  the  entire  length  of  the  shell,  measuring 
from  the  beaks';  the  nearly  straight  basal  line  is  interrupted  only  by  the 
sinuosity  caused  by  the  broad  byssal  furrow  at  the  anterior  third  of  its 
length;  posterior  end  of  the  shell  somewhat  narrowed,  terminating  in  a 
rather  abruptly  rounded  extremity  on  the  upper  portion  of  the  posterior 
outline;  cardinal  line  straight  anteriorly,  becoming  slightly  arcuate  on  the 
posterior  third. 

Surface  marked  by  numerous  concentric  lines  of  growth. 

The  generic  reference  of  this  species  is  somewhat  provisional,  as  there 
is  but  one  imperfect  right  valve  in  the  collection,  which,  although  strongly 
characterized,  does  not  give  the  hinge  structure,  and  other  important  feat- 
ures of  value  in  generic  determinations. 

Formation  and  locality. — Lower  Devonian,  Combs  Peak,  Eureka  District, 
Nevada. 

Sanguinolites?  gracilis,  n.  sp. 
Plate  iv,  fig.  10. 

Shell  slender,  elongate.  General  surface  moderately  convex,  the  upper 
margin  reflected,  forming  a  slightly  concave  lunette  along  nearly  the  entire 
length  of  the  hinge,  which  is  a  little  shorter  than  the  length  of  the  shell. 
Beaks  small  near  the  anterior  end  and  slightly  incurved. 


176  PALEONTOLOGY  OF  THE  EUEEKA  D1STEICT. 

Surface  nearly  smooth,  a  few  obscure  lines  of  growth  alone  showing 
on  the  cast  or  matrix. 

The  anterior  adductor  muscular  scar  is  of  medium  size,  and  has  a  low' 
ridge  and  sulcus  posterior  to  it  that  start  near  the  beak  and  extend  nearly 
to  the  basal  margin. 

Dimensions:  height  at  anterior  end,  1.75cm;  near  posterior  end,  2cm; 
length,  llcm. 

This  form  differs  from  the  preceding  species  in  its  more  slender  form, 
the  absence  of  a  well-defined  byssal  furrow,  and  the  more  attenuate  anterior 
extremity. 

Formation  and  locality. — Lower  Devonian  of  Brush  Peak,  Eureka  Dis- 
trict, Nevada,  and  also  at  the  same  horizon  on  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 

Sanguinolites  rigidus  W.  &  W.  (Sp.) 
Plate  xvi,  fig.  6. 

Cypricardiaf  rigida  White  &  Whitfield,  1862.    Proc.  Boston  Soc.  Nat.  Hist.,  vol.  viii, 

p.  300. 

Edmondiaf  bicarinata  Winchell,  1S63.    Proc.  Acad.  Nat.  Sci.  Philad.,  vol.  xv,  p.  13. 
Sanguinolites  rigidi  Hall,  1870.    Prelim.  Notice  Lam.  Shells,  p.  44. 

rigidus  Hall,  1883.     Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Descriptions,  p. 
16;  pi.  Ixvi,  figs.  1-19. 

The  relative  stratigraphic  position  of  this  species  in  the  Chemung 
Group  of  New  York  and  the  Upper  Devonian  beds  of  The  Gate,  northwest 
of  Eureka,  is  the  same;  and  direct  comparison  with  specimens  from  the 
Burlington  sandstones  of  Iowa  and  the  Chemung  shales  of  New  York,  shows 
the  two  forms  to  be  specifically  identical. 

Sanguinolites  ?  Sanduskyensis  Meek. 
Plato  v,  fig.  4. 

Sanguinolites?  SandusTcyensis  Meek,  1871.  Proc.  Acad.  Nat.  Sci.  Philad.,  vol.  -g^iii, 
p.  68.  Ibid.,  1873.  Geol.  Surv.  Ohio  Pal.,  vol.  i,  pt.  2,  p.  209,  pi.  xviii,  fig.  3. 

Compare  Modiomorpha  linguiformis  Hall.  Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Descrip- 
tions, p.  12,  pi.  xxxiv,  figs.  15-17,  and  M.  Hyalea,  p.  13,  pi.  xli,  fig.  28. 

The  external  form  and  characters  of  the  shell  before  me  agree  with 
those  described  by  Mr.  Meek,  as  shown  in  his  figure. 


FOSSILS  OF  THE  DEVONIAN. 


177 


In  making  an  original  generic  reference,  I  would  place  the  species  under 
Modiomorpba,  as  it  is  more  closely  related  to  the  genus  as  defined  by  Pro- 
fessor Hall  (Prelim.  Notice  Lam.  Shells,  1870.  8vo.,  pam.,  p.  72)  than 
to  Sanguinolites,  as  restricted  by  him  to  American  species.  For  the  present, 
Mr.  Meek's  provisional  reference  is  retained. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka  Dis- 
trict, Nevada. 

Sanguinolites  ventricosus  W.  &  W.  (Sp). 
Plate  xv,  fig.  13. 

Orthonota  ventricosa  White  &  Whitfield,  1862.    Proc.  Boston  Soc.  Nat.  Hist.,  vol. 

viii,  p.  297. 
Sanguinolites  ventricosus  Miller,  1877.     Cat.  Ainer.  Pal.  Foss.,  p.  203. 

Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1 ;  Plates  and  Descriptions, 
p.  16,  pi.  Ixvf,  figs.  36-42. 

The  Nevada  shell  possesses  all  the  specific  characters  of  the  examples 
of  this  species  from  the  Burlington  sandstone  of  Iowa,  differing  only  in  the 
more  angular  umbonal  ridge,  and  not  quite  as  expanded  posterior  end; 
features  reduced  or  enlarged  by  the  nature  of  the  sediment  in  which  the 
shells  are  embedded.  A  species  referred  to  this  from  the  Chemung  Group 
of  New  York  has  sharp  concentric  lines  instead  of  the  more  rounded  lines 
of  the  Burlington  species. 

Formation  and  locality. — Middle  to  Upper  Devonian,  Rescije  Hill,  west 
of  Rescue  Canon,  Eureka  District,  Nevada. 

Genus  CONOCARDIUM  Bronn. 

X 

Conocardium  Nevadensis,  n.  sp. 
Plate  xvi,  figs.  4,  4  a. 

Shell  small,  cordate  when  viewed  from  the  anterior  end,  and  subtrig- 
onal  on  a  side  view;  anterior  half  ventricose,  sloping  away  rapidly  to  the 
narrow  posterior  extremity  and  obliquely  truncate  anteriorly,  the  anterior 
slope  being  more  or  less  concave  below  the  rounded  umbonal  angle;  beaks 
rising  above  the  hinge-line,  incurved;  hinge-line  straight,  forming  an  angle 
of  about  80°  with  the  posterior,  and  110°  with  the  anterior,  margin;  hiatus 

not  observed  in  the  united  valves,  but  from  the  outline  of  the  single  valve 
12  c  D  w 


178  PALEONTOLOGY  OF  THE  EUKEKA  DISTEICT. 

it  was  of  medium  width,  and  nearly  one-half  the  length  of  the  shell  on  the 
lower  side. 

Surface  marked  by  fine  radiating  striae  on  the  body  and  anterior 
slope,  and  stronger  striae  or  ribs  on  the  alate  posterior  portion  of  the  shell ; 
traces  of  fine  concentric  striae  are  discernible,  which  under  more  favorable 
conditions  of  preservation  would  probably  be  a  prominent  feature. 

This  species  is  allied  to  a  form  from  the  Schoharie  grit  of  New  York, 
but  with  its  short  ventricose  body,  slender  posterior  extension,  and  rounded 
umbonal  angle  it  differs  from  any  described  Devonian  species  known  to  me. 

Formation  and  localities. — Lower  Devonian  horizon  of  Gray's  Canon, 
and  Comb's  Peak,  Eureka  District,  Nevada. 

Genus  PAEACYCLAS  Hall. 
Faracyclas  occidentalis  H.  &  W. 

Lucina  (Paracyclas)  elliptica,  var.  occidentalis.  Hall  &  Whitfield,  1872.  Twenty-fourth 
Ann.  Eep.  N.  Y.  State  Museum  Nat.  Hist.,  p.  189.  Twenty-seventh,  ibid., 
pi.  xii,  figs.  14-16,  1875. 

Paracyclas  elliptica,  var.  occidentalis  Hall.  Pal.  N.  Y.,  vol.  v,  pt.  1 ;  Plates  and  Expla- 
nations, p.  18,  pi.  Ixxii,  figs.  31-33. 

The  specific  resemblance  of  the  Nevada  to  the  Ohio  shell  is  so  close 
that  when  placed  in  the  same  tray  it  is  difficult  to  separate  the  two  except 
by  lithologic  characters. 

It  has  a  much  greater  vertical  range  in  Nevada  than  in  Ohio,  occurring 
near  the  base  and  the  summit  of  the  Devonian,  and  in  Ohio  only  at  the 
Upper  Helderberg  horizon. 

Formation  and  localities. — Lower  Devonian  of  Lone  Mountain;  Middle 
and  Upper  Devonian  of  Rescue  Hill,  west  of  Rescue  Canon,  and  at  The 
Gate,  northwest  of  Eureka,  Nevada. 

Genus  POSIDONOMYA  Bronn. 

Posidonomya  leevis,  n.  sp. 
Plate  iv,  fig.  6. 

Shell  thin,  broadly  truncato-ovate.  General  surface  depressed  and  but 
very  slightly  convex  towards  the  beak  on  the  rounded  umbonal  slopes. 


FOSSILS  OF  THE  DEVONIAN. 


179 


Hinge-line  straight,  not  quite  as  long  as  the  greatest  width  of  the  shell. 
Beaks  small,  situated  on  the  posterior  portion  of  the  anterior  half  of  the 
shell,  and  nearly  but  not  quite  emarginate. 

Surface  marked  by  traces  of  a  few  concentric  lines  of  growth.  No 
interior  characters  have  been  observed. 

Dimensions:  height,  2.25cm;  breadth,  2.5cm;  convexity  of  right  valve 
at  the  umbo,  2.5mm. 

In  its  smooth  surface  this  species  varies  from  typical  examples  of 
Posidonomya,  but  its  straight  hinge-line  and  general  form  ally  it  more  nearly 
to  that  genus  than  to  any  other  with  which  I  am  acquainted. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka  Dis- 
trict, Nevada,  also  at  the  same  horizon  on  Lone  Mountain,  18  miles  north- 
west of  Eureka,  Nevada. 


Posidonomya  Devonica,  n.  sp. 
Plate  iv,  fig.  7. 

Shell  thin,  small,  obliquely  truncato-ovate.  General  surface  very  much 
depressed.  Hinge-line  straight.  (Owing  to  the  breaking  away  of  the  ante- 
rior portion  this  is  not  certain,  but  if  any  deflection  from  a  straight  line 
occurs  it  is  very  slight).  Beaks  small,  situated  near  the  cardinal  margin  at 
the  anterior  third  of  the  distance  between  the  posterior  and  anterior  margins. 

Surface  marked  by  strong  concentric  lines  that  terminate  on  the  straight 
cardinal  line. 

Interior  and  hinge  characters  unknown. 

Dimensions:  height,  !4mm;  breadth,  13mm;  convexity  of  right  valve,  1.51"111. 

This  species  occurs  at  the  same  locality  as  the  preceding,  but  not  in 
the  same  layer  of  rock.  It  differs  in  form  and  surface  markings,  in  the 
latter  feature  more  closely  resembling  the  typical  forms  of  the  genus  than 
P.  Icevis. 

As  with  P.  Icevis,  we  know  nothing  of  the  hinge-line  or  interior  char- 
acters, and  have  only  the  general  form  to  go  by  in  making  the  generic 
reference,  which  renders  it  more  or  less  provisional  and  doubtful.  Com- 
paring this  species,  however,  with  Posidonomya  Bronni  Voltz,  from  the 


180  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Lias  (Pictet.  Traite  de  Pal.,  Atlas,  pi.  Ixxxii,  fig.  14),  there  is  a  striking- 
resemblance. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka  Dis- 
trict, Nevada,  and  also  at  the  same  horizon  on  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 

Genus  MICRODON  Conrad. 
CYPRICARDELLA  Hall. 

Microdon  (C.)  macrostriatus,  u.  sp. 
Plate  v,  fig.  5. 

Shell  transverse,  broadly  subovate.  General  surface  depressed,  very 
slightly  convex.  Hinge-line  more  than  half  as  long  as  the  shell.  Beaks 
small  and  situated  on  the  anterior  quarter  of  the  shell. 

Surface  marked  by  strong  concentric  lines  of  growth,  seven  in  a  dis- 
tance of  12mm  on  the  central  portion  of  the  shell. 

Dimensions:  height,  2cm;  length  about  4cm. 

In  general  form  this  species  is  not  unlike  Microdon  complanatus  Hall 
(Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations,  pi.  Ixxiv,  figs.  14-19). 
The  beaks  are  more  anterior  and  the  surface  striae  more  like  lines  or  short, 
sharp  undulations  of  growth  than  fine  striae. 

The  anterior  half  of  the  shell  is  preserved  on  one  specimen,  the  out- 
lined portion  of  fig.  5  being  taken  from  another,  in  which  the  shell  in  front 
of  the  beaks  is  broken  away. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka  Dis- 
trict, Nevada;  also  at  the  same  horizon  on  Lone  Mountain,  18  miles  north- 
west of  Eureka,  Nevada. 

Genus  ANODONTOPSIS  McCoy. 

Anodontopsis  amygdalaeforniis,  n.  sp. 
Plate  xv,  figs.  7,  7  a,  b. 

General  outline  obscurely  subtrigonal,  moderately  convex;  slope  from 
below  the  beaks  to  the  anterior  extremity  slightly  concave,  and  from  this 


FOSSILS  OF  THE  DEVONIAN. 


181 


point,  which  is  above  the  transverse  center  of  the  shell,  the  outline  curves 
down  into  the  broadly-rounded  basal  margin;  posterior  extremity  a  little 
below  the  transverse  center  and  broadly  angular,  the  line  above  rounding 
upward  into  the  cardinal  line  and  to  the  beaks  with  a  uniform  curvature; 
beaks  elevated  above  the  hinge-line,  rather  small,  and  situated  on  the  ante- 
rior third  of  the  shell. 

Surface  of  cast  with  an  obscure  anterior  muscular  scar  and  obscure 
concentric  lines  of  growth. 

In  the  absence  of  the  structure  of  the  hinge  the  generic  reference  is  ac- 
companied with  more  or  less  uncertainty,  but  in  the  light  that  the  present 
specimens  afford  the  species  is  referred  to  the  genus  Anodontopsis. 

Formation  and  localities. — Lower  Devonian  horizon  of  Lone  Mountain, 
18  miles  northwest  of  Eureka;  and  Grav's  Canon,  Eureka  District,  Nevada, 


Genus  SCHIZODUS  King. 
CYTHERODON  Hall. 

Schizodus  (Cytherodon)  orbicularis,  n.sp. 

Plate  v,  figs.  8, 8  a. 

Shell  of  medium  size ;  suborbicular,  or  subrhomboidal  in  outline.  Gen- 
eral surface  strongly  convex,  with  the  umbonal  ridge  rounded.  Beaks  small 
and  but  little  elevated  above  the  cardinal  line. 

Surface  smooth  or  marked  by  slightly  impressed  concentric  lines  of 
growth.  Interior  characters  unknown. 

Dimensions:  height,  3cm;  breadth,  3.5cm;  convexity  of  right  valve,  .75cm. 

A  small  shell  (fig.  8  a)  still  more  quadrate  in  outline  occurs  in  the  Lower 
Devonian  of  A  try  pa  Peak.  It  is  probable  that  it  is  a  young  shell  of  the 
species  under  consideration. 

In  Cytherodon  (Schizodus)  quadrangular  is  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  1, 
Plates  and  Explanations,  p.  18,  pi.  Ixxv,  figs.  31-36),  from  the  Chemung  and 
Waverly  Groups,  we  have  the  nearest  form  to  S.  ((7.)  orbicularis. 

The  beaks  in  the  former  are  more  subcentral  and  the  outline  less  sub- 
orbicular.  They  are,  however,  very  closely  allied  species. 

Formation  and  locality. — Lower  Devonian  of  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


182  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Genus  CYPRICARDINIA  Hall. 

Cypricardinia  indeuta  Conrad  (Sp.). 
Plate  v,  fig.  14;  pi.  xv,  fig.  11. 

Cypricardites  indenta  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  pt.  2,  p. 

244,  pi.  xii,  fig.  12. 

inflata  Conrad,  1842.    Ibid.,  p.  246,  pi.  xv,  fig.  2. 

Cypricardinia  inflata,  var.  subequivalvis  Hall  &  Whitfield,  1872.  Twenty-fourth  Ann. 
Rep.  N.  Y.  State  Museum  Nat.  Hist.,  p.  189.  Idem,  Twenty-seventh 
Ann.  Rep.,  1871,  pi.  xi,  figs.  2-4. 

indenta  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1;  Plates  and  Explanations, 
p.  19,  pi.  Ixxix,  figs.  6-23. 

The  Nevada  specimens  agree  closely  with  those  from  New  York  and 
the  Falls  of  the  Ohio,  no  apparent  variations  occurring  in  a  number  of  speci- 
mens except,  it  may  be,  in  some  young  shells,  a  figure  of  one  of  which  is 
given  on  plate  v,  fig.  14. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak.  Eureka  Dis- 
trict, Nevada. 

GASTEROPODA. 
Genus  PLATYCERAS  Conrad. 

Of  the  eight  species  of  Platyceras  from  the  Lower  Devonian  horizon, 
five  are  identical  with  species  of  the  Upper  Helderberg  Group  of  New  York, 
viz:  Platyceras  carinatum  Hall,  P.  conicum  Hall,  P.  dentalium  Hall,  P.  nodo- 
sum  Conrad,  and  P.  Thetis  Hall  (for  descriptions  and  synonyms,  see  Pro- 
fessor Hall's  beautiful  monograph  of  the  Devonian  Gasteropoda  of  the  State 
of  New  York,  Pal.  N.  Y.,  vol.  v,  pt.  2,  1879),  and  three  appear  to  be  distinct 
from  any  described  forms. 


Platyceras  Conradi,  n.  ep. 
Plate  xvi,  figs.  1, 1  a. 

Shell  strongly  arcuate,  the  apex  incurved,  oblique,  and  resting  against 
the  right  side  of  the  body  whorl ;  body  whorl  increasing  very  gradually  in 
size  from  the  inner  whorl  to  the  aperture ;  prominent  on  the  back  and  some- 


FOSSILS  OF  THE  DEVONIAN. 


183 


what  flattened  on  the  left  side.  Aperture  varying  from  irregularly  quadrate 
to  subquadrangular;  peristome  sinuous  and  in  some  examples  marked  by  a 
prolongation  of  the  dorsal  side  and  a  strong  sinus  on  the  right  posterior 
margin,  which  in  other  specimens  is  quite  shallow  and  carried  back  on  the 
posterior  margin. 

Surface,  as  shown  by  the  cast,  strongly  striate,  parallel  to  the  margin 
of  the  peristome,  and  marked  by  undulations  of  growth  on  the  body  whorl. 

This  species  is  allied  to  P.  Thetis  Hall  (Pal.  N.  Y.,  vol.  v,  pt  2,  p.  8,  pi. 
iii,  figs.  11-16)  in  the  general  form  of  the  body  whorl,  but  differs  widely  in 
its  more  oblique,  arcuate  upper  portion,  a  feature  distinguishing  it  from  P. 
symmetricum  Hall  (loc.  cit.,  p.  9,  pi.  iii,  figs.  17-25)  and  other  allied  species. 

Formation  and  locality. — Lower  Devonian  horizon  of  Comb's  Peak,  Eu- 
reka District,  Nevada. 

Platyceras  uodosum  Conrad. 
Plate  vi,  figs.  5,  5  a,  6. 

Platyceras  nodosus  Conrad,  1841.    Fifth  Ann.  Eep.  Pal.  State  of  N.  Y.,  p.  56. 

nodosum  Hall,  1859.   Pal.  N.  Y.,  vol.  iii, p.  473,  pis.  cxv,  figs.  1-6 ;  cxvi,  figs.  1-4. 
dumosum  and  P.  dumosum,  var.  rarispinum  Hall,  1876.    Pal.  N.  Y.,  Illustra- 
tions of  Devonian  Fossils,  Gasteropoda,  plates  v  and  vii. 
nodosum  Hall,  1879.    Pal.  K  Y.,  vol.  v,  pt.  2,  p.  17,  pi.  vii,  figs.  4,  5. 

We  have  very  little  hesitancy  in  identifying  the  species  from  Lone 
Mountain  with  specimens  from  the  Oriskany  sandstone  of  Knox,  N.  Y.,  and 
the  figures  of  P.  nodosum  given  by  Professor  Hall.  The  Nevada  shell  may 
expand  a  little  more  rapidly  along  the  inner  volutions,  but  of  this  there  is 
scarcely  any  proof.  The  general  form  and  nodose  character  of  the  surface 
vary  little  from  the  same  features  in  the  New  York  specimens ;  not  as  much 
as  the  specimens  from  the  same  locality  vary  from  each  other. 

In  New  York  the  species  ranges  from  the  Oriskany  sandstone  to  the 
Upper  Helderberg  Group.  In  Nevada  it  is  as  yet  known  only  from  the 
Lower  Devonian  in  association  with  other  Upper  Helderberg  species. 

Formation  and  locality. — Lower  Devonian  of  Lone  Mountain,  18  miles 
northwest  of  Eureka,  Nevada. 


184  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Platyceras  undulatum,  n.  sp. 
Plate  vi,  figs.  2,  2  a. 

Shell  small,  depressed;  apex  incurved;  body  whorl  expanding  quite 
rapidly  on  the  outer  half  of  the  volution ;  dorsum  subangular  and  with  a 
shallow  depression  on  each  side;  a  second  rounded  carina  appears  on  the 
left  side.  The  body  volution  is  marked  by  concentric  undulations  that  are 
slightly  sinuous ;  on  the  dorsal  carina  a  node  appears  at  the  crossing  of  the 
undulations.  Aperture  subcircular;  peristome  sinuate;  the  undulations 
corresponding  to  the  outline  of  its  margin. 

Surface  of  shell  unknown. 

There  is  but  one  specimen  of  this  species  in  the  collections,  but  it 
is  so  well  distinguished  by  its  general  form  and  the  presence  of  trans- 
verse undulations  that  there  is  little  danger  of  confusing  it  with  other  spe- 
cies. It  is  of  the  same  type  as  Platyceras  Newberryi  Hall  (Pal.  N.  Y.,  vol. 
iii,  p.  33H,  pi.  Ixiii,  figs.  14o-e)  of  the  Lower  Helderberg  Group,  and  the 
undulations  in  the  cast  may  owe  their  origin  to  the  presence  of  rows  of 
nodes  or  spines  on  the  shell. 

Formation  and  locality. — Lower  Devonian,  Brush  Peak,  Eureka  Dis- 
trict, Nevada. 

Platyceras  thetiforme,  n.  sp. 
Plate  vi,  figs.  4,  4  a,  6. 

Shell  obliquely  arcuate  from  the  base  with  the  apex  incurved,  the  nu- 
cleus making  about  one  volution;  body  whorl  gradually  increasing  in  size 
to  the  aperture;  on  the  back  it  is  strongly  carinate;  the  left  side  is  evenly 
rounded  and  the  right  a  little  flattened,  producing  a  slight  carina  where 
uniting  with  the  anterior  surface. 

Form  of  aperture  unknown.  Surface  markings  not  determined.  The 
strong  carina  on  the  back  distinguishes  this  species  from  P.  Thetis  Hall, 
and  its  gradually  expanding  body  volution,  so  much  like  that  of  P.  Thetis, 
from  P.  carinatum. 

Formation  and  locality. —  Lower  Devonian  of  Brush  Peak,  Eureka  Dis- 
trict, Nevada,  in  association  with  Platyceras  Conradi,  Platyostoma  lineatum,  etc. 


FOSSILS  OF  THE  DEVONIAN. 


185 


Genus  PLATYOSTOMA  Conrad. 
Platyostoma  Hneatum  Conrad. 

Platyostoma  lineata  Conrad,  1842.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  viii,  p.  276,  pi. 

xvii,  fig.  7. 

Hall,  1876.  Pal.  N.  Y.,  Illustrations  of  Devonian  Fossils,  Gas- 
teropoda, pi.  ix,  figs.  1-21;  Idem.,  Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  21, 
pi.  x,  figs.  1-21,  1879. 

The  only  differences  to  be  noted  between  the  Nevada  shells  and  those 
of  this  species  from  the  Upper  Helderberg  and  Hamilton  Groups  of  New 
York  are,  that  the  former  average  a  little  less  in  size  and  the  surface  can- 
cellation, formed  by  the  crossing  of  the  revolving  and  concentric  striae,  is 
almost  obsolete;  this  latter  feature,  however,  is  frequently  seen  in  speci- 
mens from  both  the  New  York  formations. 

Formation  and  locality. — Lower  Devonian  of  Comb's  Peak,  Eureka 
District,  Nevada. 

Genus  EUOMPHALUS  Sowerby. 

Euomphalus  Eurekensis,  n.  sp. 
Plate  xvi,  figs.  2,  2  a. 

Shell  large,  discoidal,  lower  side  broadly  umbilicate.  Volutions  four 
or  more,  nearly  in  the  same  plane,  varying  somewhat  in  different  individu- 
als; barely  contiguous,  gradually  and  uniformly  expanding  from  the  apex; 
section  subcircular  or  transversely  subovate,  the  diameters  being  as  4  to  5, 
to  the  outer  portion  of  the  last  volution  where  there  is  a  slight  angularity 
developed  on  the  upper,  outer  margin.  Aperture  slightly  expanded,  with 
a  slight  sinus  on  the  upper  margin. 

Surface  marked  by  concentric  striae  parallel  to  the  margin  of  the  aper- 
ture. 

The  largest  individual  observed  of  this  species  has  a  transverse  diam- 
eter of  80mm,  measuring  across  the  volutions.  The  inner  volutions  have 
been  decollated  or  removed  during  the  maceration  of  the  shell,  leaving 
only  the  outer  volution  and  one-half  of  the  next  preceding  it,  the  termi- 
nation of  which  rises  slightly  above  the  plane  of  the  outer  volution.  A 
specimen  55mm  across  the  volutions  has  the  spire  depressed  to  the  plane  of 


186  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

the  periphery  of  the  outer  volution,  and  in  another  it  is  still  more  depressed, 
the  umbilicus  being  nearly  flat. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  and  Atrypa  Peak  Ridge,  Eureka  District,  Nevada. 


Euomphaltis  (Phanerotinus)  laxus  Hall. 
Plate  vi,  fig.3. 

Euomphalm  laxm  Hall,  18(51.    Descriptions  of  New  Species  of  Fossils,  etc.,  p.  26. 

1862.    Fifteenth  Ann.  Eep.  N.  Y.  State  Cab.  Nat,  Hist.,  p.  54, 

pi.  vi,  fig.  2. 
(Ecculiomphalus  ? )  laxus  Hall,  1876.     Pal.  N.  Y.,  Illustrations  of  Devonian 

Fossils,  Gasteropoda,  pi.  xvi,  figs.  16-18. 
comes  Hall,  1876.    /&«#.,  pi.  xvi,  figs.  8,  9. 
(Phanerotinus}  laxus  Hall,  1879.     Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  60,  pi.  xvi, 

figs.  8,  9,  16-18. 

Compare  Phanerotinus  paradoxus  Winchell,  1863.    Proc.  Acad.  Nat.  Sci. 
Philad.,  vol.  xv,  p.  21. 

The  representatives  of  this  species  from  the  Upper  Devonian  are 
smaller  than  the  average-sized  specimens  from  the  Hamilton  Group  of  New 
York.  In  the  disjoined  volutions,  broadly  umbilicated  under-side,  gradual 
expansion  from  the  apex,  circular  section,  and  concentric  surface  striae, 
the  species  is  identical  with  E.  laxus. 

It  seems  somewhat  improbable  that  a  form  of  this  character  should 
range  from  the  Upper  Helderberg  and  Hamilton  Groups  of  New  York  up 
to  the  summit  of  the  Devonian  in  Nevada,  but  with  the  large  number  of 
species  which  we  know  are  common  to  the  two  localities  and  the  identity  in 
form  between  the  shells  of  this  species  from  each  locality,  there  appears  no 
other  way  than  to  place  them  under  the  same  specific  name. 

There  is  a  species  associated  with  E.  laxus  that  corresponds  closely  to 
Euomphalus  (S.)  Hecale  Hall,  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  59,  pi.  xvi,  figs. 
10-14),  from  the  Chemung  Group  of  New  York  and  Pennsylvania,  the 
difference  being  in  the  more  rapid  expansion  of  the  outer  volution.  The 
specimens  at  hand  are  too  imperfect  for  specific  description. 

Formation  and  locality. — Upper  Devonian  ;  The  Gate,  northwest  of 
Eureka,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


187 


Genus  ECOULIOMPHALUS  Portlock. 

Ecculiomphalus  Devonicus,  n.  sp. 

Plate  vi,  figs.  6,  6  a. 

Shell  discoid.  Volutions,  one  or  two?,  widely  separated;  rapidly 
enlarging;  section  subtriangular,  rounded  a  little  above  and  also  from  the 
inner  and  outer  margins  down  to  the  obtusely  angulated  ventral  surface. 

Surface  unknown. 

A  comparison  with  the  figures  given  by  Portlock  of  the  types  of  the 
genus  E.  Bucklandi  and  E.  minor  (Rep.  Geol.  Londonderry,  Tyrone,  &c., 
1847,  pp.  411,  412,  pi.  xxx,  figs.  10-12)  shows  our  Devonian  species  to  be 
generically  identical  with  them,  although  the  inner  portion  of  the  whorl  or 
whorls  is  broken  away,  and  the  surface  of  the  shell  destroyed. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak;  Eureka 
District,  Nevada. 


Genus  STRAP AKOLLUS  Montfort. 

Straparollus  Newarkensis,  n.  sp. 

Plate  xvi,  figs.  7,  7  a. 

Shell  small ;  spire  slightly  elevated  above  the  general  plane  Umbili- 
cus narrow,  scarcely  exposing  the  inner  whorls.  Volutions  four  or  five, 
very  gradually  expanding  to  the  outer  volution,  which  increases  a  little  more 
rapidly;  transverse  section  rounded,  subangular  or  obscurely  subquad- 
rangular;  obtusely  angular  above  and  below  with  a  slightly  .oblique,  convex, 
or  flattened  periphery;  gently  rounded  on  the  upper  surface  to  the  strongly 
defined  suture,  and  on  the  lower  surface  to  the  more  sharply  rounded  edge 
of  the  umbilicus. 

Surface  of  the  shell  marked  by  concentric  striae  and  lines  of  growth 
parallel  to  the  margin  of  the  aperture.  From  the  suture  they  curve  slightly 
backward  over  the  upper  margin,  and  then  forward  to  a  little  below  the 
center  of  the  periphery,  recurving  gently  backward  to  the  margin  of  the 
umbilicus. 


188  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

This  species  is  closely  related  to  several  described  forms,  but  differs 
chiefly  in  having  an  unusually  narrow  umbilicus. 

Formation  and  locality. — Central  portion  of  the  Devonian  limestone; 
Newark  Mountain,  Eureka  District,  Nevada. 

Genus  PLATYSCHISMA  McCoy. 

Platyschisma  ?  McCoyi,  n.  sp. 

Plate  xvii,  figs.  1,  la-c. 

Shell  subdiscoidal  in  its  younger  stages  of  growth,  becoming  more  or 
less  trochiform  in  the  adult ;  spire  moderately  elevated.  Volutions  five  or 
six,  expanding  gradually  from  the  apex  to  the  aperture;  periphery  rounded, 
acute;  upper  surface  with  a  distinct  depression  just  above  the  periphery,  that 
increases  in  width  with  the  enlargement  of  the  volutions  so  as  to  give,  in 
the  adult,  a  concavity  to  the  surface  of  the  last  volution;  under  side  of 
volutions  slightly  convex;  transverse  section  subrhombic.  Aperture  irregu- 
larly rounded  with  a  sinuosity  in  the  upper  margin. 

Surface  marked  by  lines  of  growth  that  curve  back  to  a  narrow  line 
or  band,  and  then  forward  to  the  periphery  of  the  whorl;  on  the  last  whorl 
these  lines  have  a  broad  retral  curve  from  the  periphery  to  the  umbilicus. 

This  species  differs  from  the  generic  type  of  Platyschisma  in  having  a 
closed  umbilicus,  and  thick  shell,  but  in  the  typical  species  the  umbilicus 
is  very  small,  and  M.  Chenu  has  placed  a  thick  shell,  P.  applanatus,12  as 
representing  the  genus.  In  other  respects  the  generic  characters  are  those 
of  Platyschisma,  the  narrow  line  formed  by  the  meeting  of  the  strigs  not 
forming  a  true  band  as  in  Pleurotomaria. 

Formation  and  locality. — Central  portion  of  the  Devonian  limestone ; 
Newark  Mountain,  Eureka  District,  Nevada. 

Platyschisma?  ambiguum,  n.  sp. 
Plate  xvii,  figs.  3,  3 a. 

Shell  subdiscoidal,  spire  short,  obtuse.  Volutions  about  five,  angular 
and  closely  united  at  the  suture,  forming  a  slightly  convex,  unbroken  slope 

"Mannal  de  Conch yliologie,  p.  235,  fig.  1382,  1859. 


FOSSILS  OF  THE  DEVONIAN. 


189 


from  the  apex  to  the  acute  periphery ;  transverse  section  subtrigonal ;  upper 
surface  with  a  slight  depression  below  the  center;  under  surface  slightly 
convex.  Umbilicus  closed.  Aperture  nearly  round,  with  the  inner  lip 
reflected. 

Surface  transversely  marked  by  lines  of  growth  that  have  a  retral 
curve  on  the  central  portion  of  the  upper  surface  of  the  volution. 

This  species  is  doubtfully  referred  to  Platyschisma,  owing  to  its  having 
a  reflected  inner  lip  and  closed  umbilicus.  The  latter,  however,  was  prob- 
ably open  in  the  earlier  stages  of  growth,  having  been  closed  by  the  outer 
volutions.  The  general  aspect  of  the  species  is  much  like  that  of  several 
forms  of  Pleurotomaria  occurring  in  the  Silurian  formations,  but  the 
absence  of  a  definite  mesial  band  and  the  presence  of  the  broad  sinuosity 
in  the  upper  portion  of  the  aperture,  shown  by  the  retral  curve  of  the 
lines  of  growth,  distinguishes  it  and  places  its  generic  relations  with  Platy- 
schisma or  an  allied  genus. 

Formation  and  locality. — Upper  horizon  of  the  Devonian  limestone,  The 
Gate,  Eureka  District,  Nevada. 


Genus  CALLONEMA  Hall. 

Callonema  occidentalis,  n.  sp. 

Plate  xvi,  figs.  3,  3  a. 

Shell  subglobose,  depressed.  Spire  slightly  elevated,  consisting  of 
about  four  rounded  volutions  very  regularly  increasing  in  size  from  the 
apex  to  the  aperture;  suture  slightly  depressed  and  marking  the  periphery 
of  the  preceding  volutions. 

Surface  exfoliated.  The  cast  shows  a  few  obscure  transverse  strise  that 
curve  gently  backward  from  the  suture  towards  the  periphery. 

The  general  aspect  of  this  species  is  similar  to  that  of  Callonema  imitator 
H.  and  W.  (Hall,  Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  53,  pi.  xiv,  figs.  Itf,  17)  of  the 
Upper  Heiderberg  Group  of  the  State  of  Indiana.  It  differs  in  having  a 
more  depressed  spire,  and  the  volutions  expanding  a  little  more  rapidly. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Eureka  District,  Nevada. 


190  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Genus  LOXOKEMA  Phillips. 

Casts  of  five  species  of  spiral  univalves  occur  in  the  lower  fossiliferous 
beds  of  the  Devonian  limestone.  They  are  in  such  a  condition  of  preserva- 
tion as  to  render  it  difficult  in  the  absence  of  surface-markings  to  determine 
their  relations,  although  they  evidently  belong  to  the  genus  Loxonema. 
Professor  Hall  met  with  a  group  of  species  in  the  Upper  Helderberg  Group 
of  the  State  of  New  York  in  a  similar  condition,  and  assigned  specific  names 
to  those  differing  widely  in  form  and  proportions  from  those  already  de- 
scribed so  as  to  be  distinguished  by  these  characters  alone.  This  course  is 
the  only  one  to  pursue  with  such  meager  and  unsatisfactory  material  when 
it  is  desirable  to  specify  the  different  forms,  and  as  this  is  the  case  with  the 
Nevada  species,  two  of  the  five  are  described  and  referred  to  Loxonema,  and 
a  descriptive  note  given  with  each  of  the  remaining  three,  one  of  which  is 
provisionally  referred  to  Loxonema  subattenuata,  of  the  Upper  Helderberg 
Group  of  New  York. 

Loxonema  Eurekensis,  n.  sp. 
Plate  xvi,  fig.  8. 

Shell  turretiform,  elongate,  robust;  spire  somewhat  rapidly  ascending, 
angle  of  divergence  from  the  apex,  25°.  Volutions,  eleven  or  more  in  a 
specimen  of  110mm  in  length,  slightly  convex,  and  very  gradually  expand- 
ing from  the  apex. 

Surface  unknown. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone; 
divide  at  the  head  of  the  Reese  and  Berry  Canon,  Eureka  District,  Nevada. 


Loxonema  nobile,  a.  sp. 
Plate  xvi,  fig.  9. 

Shell  robust,  elongate,  turretiform;  spire  rapidly  ascending,  angle  of 
divergence  from  the  apex,  15°.  Volutions  regularly  increasing  from  the 
apex,  slightly  convex ;  the  three  lower  volutions  have  a  united  length  of 

50mm. 


FOSSILS  OF  THE  DEVONIAN. 


191 


This  and  the  preceding  species  have  slight  indications  of  uninterrupted 
concentric  lines  of  growth,  so  that  the  generic  reference  will  probably  be 
sustained  on  the  finding  of  more  perfect  specimens.  They  are  large,  robust 
forms,  differing  very  much  from  each  other  and  from  any  described  species 
occurring  at  the  same  geologic  horizon. 

Formation  and  locality.  —  Lower  horizon  of  the  Devonian  limestone, 
Comb's  Mountain,  Eureka  District,  Nevada, 


Loxonema  ?  subattenuatum  Hall  ? 

Lojconema  subattemiata  Hall,  1861.  Descriptions  of  New  Species  of  Fossils,  etc.,  p.  24. 
Mem.,  1862.  Fifteenth  Aun.  Rep.  N.  Y.  State  Cab.  Nat.  Hist,  p.  52.  Idem., 
1876.  Pal.  N.  Y.,  Illustrations  of  Devonian  Fossils,  Gasteropoda,  pi.  xiii, 
figs.  1-3.  Idem.,  1879.  Pal.  N.  Y.,  vol.  v,  pt,  2,  p.  40,  pi.  xiii,  figs.  1-6. 

The  illustrations  of  this  species  in  the  Paleontology  of  New  York  do 
not  show  the  surface  characters,  which  restricts  the  comparison  to  the  casts; 
^imong  these  the  differences  between  the  two,  L.  subattenuatum  and  the  Ne- 
vada form,  are  so  slight  as  to  make  it  impossible  to  separate  them  on  good 
specific  characters. 

The  species  occurs  at  Comb's  Peak,  in  the  Lower  Devonian,  and  at  the 
same  relative  horizon  in  Gray's  Canon,  Eureka  District,  Nevada. 


Loxonema  approximatum,  u.  sp. 
Plate  vi,  fig.  7. 

Shell,  terebriforrn;  spire  rapidly  ascending,  volutions  slightly  convex, 
increasing  regularly  from  the  apex,  the  last  one  a  little  vertical;  six  in  the 
length  of  2J  inches  from  the  base.  Aperture  subelliptical. 

Surface  as  shown  on  the  inner  cast,  marked  by  moderately  strong,  not 
closely  arranged,  longitudinal  striae  that  are  nearly  transverse  to  the  volu- 
tions ;  the  .striae  arch  backward  very  slightly. 

The  description  of  this  species  is  nearly  identical  with  that  of  Loxone- 
ma  styliola  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  y,  p  48,  pi.  xiv,  figs.  8,  y)  from  the 
Chemung  Group  of  New  York.  It  differs  only  in  the  more  elongate  form 


192  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

of  the  volutions  and  the  presence  of  stronger  surface  striae,  as  shown  in  the 
cast.  The  specific  distinction  is  made  on  the  difference  in  form  of  the  volu- 
tions. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka  Dis- 
trict, Nevada. 

Loxonema  ?  (sp.  undt.) 

Shell  turretiform,  elongate;  angle  of  divergence  from  the  apex,  13°  to 
15°.  Volutions  gradually  enlarging,  broad,  moderately  convex.  Surface 
unknown. 

This  species  is  represented  by  a  fragment  preserving  three  of  the  lower 
volutions.  It  is  distinguished  by  its  elongate,  tapering  spire,  and  broad  vo- 
lutions, resembling  in  this  respect  Loxonema  nolile,  but  differing  in  the 
greater  convexity  and  form  of  the  volutions. 

Loxonema  (sp.  uudt.) 

Shell  terebriform.  Spire  rapidly  ascending;  angle  of  divergence  about 
12°.  Volutions  narrow,  rounded,  gradually  expanding.  Surface  obscurely 
shown  by  faint  striae,  which  bend  slightly  backward  a  little  below  the  suture 
and  make  a  gentle  curve  forward  to  the  base  of  the  volution. 

This  and  the  preceding  species  are  associated  with  Loxonema  /  sulat- 
teniiatuin  !  and  Belleroplion  perplexa,  in  the  lower  fossiliferous  horizon  of  the 
Devonian  limestone  of  Gray's  Cafion,  Eureka  District,  Nevada. 

Genus  BELLEROPHON  Moutfort. 

Of  the  six  species  represented  in  the  collections  from  the  Devonian 
limestone,  two  are  undescribed  and  four  are  either  identical  with  species 
described  by  Professor  Hall,  from  the  Devonian  strata  of  the  State  of  New 
York,  or  so  closely  allied  to  them  that  the  grounds  for  a  specific  separation 
are  not  apparent  in  the  specimens  at  hand.  With  a  large  number  of  more 
perfectly  preserved  specimens  for  comparison,  it  may  be  that  some  of  the 
identifications  will  prove  to  be  incorrect  and  to  have  been  based  on  insuffi- 
cient material. 


FOSSILS  OF  THE  DEVONIAN. 


193 


Bellerophon  perplexa,  n.  sp. 
Plate  xvii,  figs.  6,  (i  a,  &. 

Shell  subglobose,  the  transverse  and  lateral  diameters  being  27mm  and 
33mm,  respectively,  in  a  medium-sized  specimen.  Volutions  five  or  six, 
broadly  rounded  on  the  dorsum,  subangular  on  the  dorso-lateral  angle  of 
each  volution,  and  sloping  rapidly  into  the  broad,  open  umbilicius  from  the 
dorso-lateral  angle.  Each  volution  embraces  the  dorsal  surface  of  the  pre- 
ceding, leaving  the  entire  umbilical  slope  of  each  exposed.  The  extreme 
transverse  section  of  each  volution  is  equal  to  four  times  the  lateral  section 
as  it  is  measured  midway,  or  at  the  carina.  The  aperture  is  probably  sim- 
ilar in  form  to  the  transverse  section  of  the  last  volution,  as  in  a  number  of 
examples  examined  no  evidence  of  any  expansion  was  observed.  The  dor- 
sum  has  a  narrow,  well-defined  carina. 

Test  varying  in  thickness  from  .75mm  to  1.50mm,  with  the  variation  in 
the  size  of  the  shell. 

Surface  marked  by  strong  striae;  originating  on  the  inner  margin  of  the 
umbilical  lobe  they  cross  it  obliquely,  curving  slightly  and  extending  back- 
ward at  an  angle  of  45°  to  the  dorso-lateral  angle  over  which  they  curve, 
retaining  a  backward  slope  of  15°  to  the  dorsal  carina. 

The  largest  specimen  in  the  collection  has  a  transverse  diameter  of 
50mm.  The  test  is  removed  from  the  outer  portion  of  the  last  volution,  the 
mold  retaining  only  the  slight  dorsal  carina,  a  feature  that  in  another  speci- 
men is  obsolete ;  this,  however,  is  rarely  the  case  as  in  most  examples  it 
occurs  on  the  outer  volution  and  may  be  traced  on  breaking  away  the 
volutions  to  the  second  or  third,  where  the  transverse  diameter  is  five  mil- 
limeters. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Gray's  Canon  and  Atrypa  Peak,  Eureka  District,  Nevada. 

Bellerophon  Combsi,  n.  sp. 
Plate  xvii,  figs.  9,  9  a,  I. 

Form  large,  robust,  subglobose;  exterior  shell  unknown.     In  the  cast 
the  body  volution  is  large,  nearly  if  not  quite  concealing  the  inner  volu- 
tions; broadly  rounded  on  the  dorsum  and  gradually  expanding  towards 
13  c  D  \v 


19  4  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

the  transversely  ovate  aperture;  a  narrow  dorsal  cariria  is  distinctly  shown 
on  the  cast,  and,  very  obscurely,  traces  of  transverse  striae. 

This  is  the  largest  of  the  several  species  occurring  in  the  Devonian 
limestone  of  Nevada.  Its  length  is  48mm;  transverse  section  midway  of  the 
outer  volution  30mm,  near  the  aperture  46nT 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Eureka  District,  Nevada. 

Bellerophon  lyra  Hall  (Pal.  N.  Y.,  vol.  V,  pt.  2,  p.  113,  pi.  xxiii,  figs.  1,  17-20). 

A  single  specimen  that  corresponds  in  form  and  surface  markings  to 
this  species  occurs  in  the  Devonian  limestone  on  the  eastern  side  of  the 
District.  It  has  been  slightly  worn  by  exposure  to  the  weather,  but  not  so 
much  as  to  remove  the  fine,  undulating,  revolving  striae. 

Bellerophon  Leda  Hall  (Pal.  K.  Y.,  vol.  V,  pt.  2,  p.  110,  pi.  xxiii,  figs.  2-16). 

The  Nevada  form  is  a  little  less  flattened  on  the  dorsum,  and  the  dorsal 
carina  is  more  prominent,  as  are  the  revolving  striae;  this,  however,  is  rather 
the  result  of  a  difference  in  the  conditions  of  preservation  than  of  absolute 
differences  in  the  shells;  the  New  York  specimens  usually  occurring  in  the 
argillaceous  shales  or  shaly  limestones  have  suffered  by  compression. 

Bellerophon  Maera  Hall?  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  119,  pi.  XXV,  figs.  9-14;    pi.  xxvi, 
figfr.  19-24>. 

A  fragment  from  the  higher  beds  south  of  The  Gate  has  a  thick  test 
thickly  studded  with  rows  of  pustules  in  a  manner  similar  to  that  of  B. 
Mcera  of  the  Chemung  Group  of  the  State  of  New  York.  The  general 
form  of  the  volutions  and  dorsal  carina  also  adds  to  the  strength  of  the 
comparison 

Bellerophon  Pelops  Hall?  (Pal.  1ST.  Y.,  vol.  v,  pt.  2,  p.  95,  pi.  xxii,  figs.  7-13). 

Associated  with  B.  Leda,  there  is  a  form  that  corresponds  to  one  of  the 
varieties  of  this  species  from  the  Upper  Helderberg  limestone  of  the  State 
of  New  York.  The  transverse  striae  of  the  surface  of  the  body  volution 
bending  backward  towards  the  dorsal  carina  and  the  expanded  aperture 
show  in  the  Nevada  specimen. 


FOSSILS  OF  THE  DEVONIAN. 


195 


Genus  SCOLIOSTOMA  Braun. 

Scoliostoma  Americana,  n.  sp. 
Plate  vi,  figs.  1,  1  a-e. 

Shell  small,  cylindro-conical  exclusive  of  the  expanded  inner  lip  of  the 
aperture;  apex  obtuse;  whorls  five,  slightly  convex  Aperture  contracted 
and  turned  obliquely  outward  and  backward  at  right  angles  to  the  outer 
surface  of  the  last  whorl;  outer  lip  somewhat  thickened  and  rounded;  inner 
lip  expanded,  extending  up  on  to  the  whorls  and  directed  outward;  a  swell- 
ing occurs  opposite  the  outer  lip  that  occupies  its  lower  central  portion; 
margin  of  inner  lip  very  thin.  Umbilicus  concealed.  Shell  rather  thick. 

Surface  of  shell  marked  by  a  few  concentric  strise  of  growth. 

This  is  a  most  interesting  form,  as  it  is  the  first  species  of  the  genus 
from  American  rocks,  and  its  occurrence  in  the  Devonian  limestones  of 
Nevada  is  such  that,  when  finding  only  a  few  fragments  of  the  spire,  we 
were  led  to  consider  it  a  land  shell,  the  short,  obtuse  form  recalling  species 
of  the  genus  Pupa. 

S.  Americana  departs  somewhat  from  the  typical  species  S.  Dannen- 
bergii  Braun  1838,  (Neues  Jahrbuch,  Min.  Geo.  Geol.  und  Petrefak,  p.  29S, 
taf.  ii,  figs.  B,  1—4)  in  having  the  aperture  contracted  and  the  inner  lip  more 
expanded,  but  there  are  no  differences  that  appear  to  be  of  more  than  spe- 
cific value. 

Formation  and  localities. — Lower  Devonian  of  Atrypa  Peak,  and  Brush 
Peak,  Eureka  District,  Nevada. 

This  species  is  associated  with  Productus  subaculeatus,  Spirifera  undifera, 
Atrypa  reticularis,  Goniophora  perangulata,  Platyceras  dentalium,  P.  carinatum, 
Belleroplton  perplexa,  etc. 


Genus  METOPTOMA  Phillips. 

Metoptoma  ?  Devonica,  n.  sp. 

Plate  xvii,  figs.  2,  2  a. 

Shell  conical,  broadly  rounded  or  truncated  at  the  posterior  margin; 
uniformly  rounded  on  the  lateral  and  anterior  margins;  apex  posterior  and 


196  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

terminating-  within  the  margin;  the  slope  from  the  apex  is  very  slightly 
convex;  height  a  little  less  than  the  postero-anterior  diameter;  test  about 
lmm  in  thickness. 

Surface  markings  obscured  by  the  exfoliation  of  portions  of  the  test 
and  the  adherence  of  the  matrix;  but  strong,  radiating  striae  lmm  distant 
from  each  other,  and  a  few  short  undulations  of  growth,  are  shown  on  the 
postero-lateral  faces. 

Dimensions:   height,  17mm;  length,  18mm;  breadth,  22mm. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone;  west 
side  County  Peak,  Eureka  District,  Nevada. 


PTEROPODA. 
Genus  TENTACULITES  Schlotheim. 

Of  the  four  species  of  the  genus  Tentaculites  now  known  to  occur  in 
the  lower  horizon  of  the  Devonian  limestone,  three  appear  to  be  specifically 
identical  with  well-recognized  species  of  the  Lower  Devonian  of  the  State 
of  New  York,  while  the  remaining  form  is  distinguished  only  by  the  surface 
characters,  which  are  often  unreliable  owing  to  the  imperfect  preservation 
of  the  test.  This  is  illustrated  by  Tentaculites  gracilistriatus,  where,  on  the 
same  block  of  limestone,  specimens  occur  preserving  the  annulations  and 
fine  striae,  and  others  on  which  it  is  exceedingly  difficult  to  determine  either 

The  species  are  identified  by  comparisons  with  specimens  from  New 
York,  and  also  with  the  beautiful  illustrations  and  careful  descriptions  in  the 
Paleontology  of  New  York  (vol.  v,  part  2). 

Tentaculites  gracilistriatus  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  173,  pi.  xxxi,  figs.  12-14,  and 
pi.  xxxi  A,  figs.  37-47). 

This  neat  and  strongly  defined  species  occurs  in  the  greatest  numbers 
and  is  the  most  widely  distributed  of  the  forms  found  in  the  Eureka  Dis- 
trict. It  posesses  all  the  characters  given  it  by  its  author  in  describing-  the 
New  York  types;  the  variation  in  the  form  and  prominence  of  the  annula- 
tions, the  solid  apical  portion  devoid  of  annulations,  and  the  crowded  longi- 
tudinal striae  are  the  same  in  each,  as  also  the  general  form  and  dimensions. 


FOSSILS  OF  THE  DEVONIAN. 


197 


In  New  York  it  is  associated  with  Styliola  fissureUa,  a  species  that  occurs 
with  it  at  all  the  localities  known  in  Nevada. 

Tentaculites  scalariformis  Hall  (Pal.  N.  Y.,  vol.  V,  pt.  2,  p.  167,  pi.  xxxi,  figs.  3-11). 

The  identification  of  this  species  is  by  the  characters  of  the  internal 
mold,  the  robust  form,  and  the  shape  and  regularity  of  the  annulations.  It 
has  not  been  observed  in  association  with  Styliola  fissureUa,  or  other  congen- 
eric species. 

Professor  Hall  states  that  this  species  has  a  geographic  range  of  over 
700  miles  as  known  to  him,  being  found  in  the  strata  of  the  Upper  Helder- 
berg  limestone  in  New  York,  Ohio,  and  Indiana. 

Tentaoulites  attenuates  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  170,  pi.  xxxi,  figs.  19,  20). 

The  Nevada  specimens  of  this  species  are  the  same  in  the  character  of 
the  surface  markings  and  the  irregularity  of  the  annulations  on  the  slender 
tube,  but  the  species  does  not  appear  to  have  been  as  gregarious  in  habit 
as  in  the  Hamilton  Group. 

Tentaculites  bellulua  Hall?  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  169,  pi.  xxxi,  figs.  15-18;  and  pi. 
xxxi  A,  figs.  48-51). 

There  occur  in  association  with  the  preceding  species  a  few  specimens 
that  are  closely  allied  to  T.  bellulus.  They  have  the  same  numerous,  sharp, 
regular  annulations  and  attenuate  tube,  but  differ  in  being  smaller,  and  in 
the  absence  of  the  surface  markings  mentioned  by  the  author  of  the  species. 


Genus  STYLIOLA  Le  Sueur. 
Styliola  fissureUa  Hall  (Pal.  N.  Y.,  vol.  V,  pt.  2,  p.  178,  pi.  xxxi  A,  figs.  1-30). 

It  does  not  appear  to  be  possible  to  separate  this  minute  form  from  the 
species  as  it  occurs  in  New  York.  It  ranges  through  the  fossil-bearing 
Devonian  limestone  from  the  lower  horizon  at  Lone  Mountain  to  the  highest 
beds  at  The  Gate,  northwest  of  Eureka,  Nevada. 

Styliola  fissureUa  var.  intermittens  Hall  (Pal.  N.  Y.,  vol.  V,  pt.  2,  p.  177,  pi.  xxxi  A,  figs. 
11-17.) 

This  elongate  form  is  represented  in  the  upper  strata  at  The  Gate, 
northwest  of  Eureka,  Eureka  District,  Nevada. 


198  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Professor  Hall,  in  speaking-  of  Styliola  fissurella,  says: 

"In  its  geographical  distribution,  the  S.  fissurella  has  a  remarkable 
range,  being  known  throughout  the  entire  extent  of  the  State  of  New  York 
from  east  to  west,  a  distance  of  more  than  300  miles.  It  also  occurs  in  the 
State  of  Indiana,  which  gives  it  a  geographical  extension  of  more  than  700 
miles  in  a  direct  line  from  its  most  easterly  locality. 

"In  some  of  its  phases  it  does  not  seem  possible  to  separate  this  spe- 
cies from  Styliola  clavulus  of  Barrande  by  any  external  or  internal  characters 
thus  far  described  or  illustrated.  The  fossils  are  minute,  smooth,  or  striated 
acicular  tubes,  presenting  in  all  respects  similar  features  and  having  similar 
associations,  and  they  are  of  the  same  geological  age  in  the  two  countries. 
In  very  numerous  examples  these  fossils  are  striated  transversely  or  longi- 
tudinally, and  not  unfrequently  the  two  sets  of  striae  are  visible  on  the  same 
specimen.  These  are  apparently  only  varieties  of  form  and  condition  of 
the  Styliola  fissurella" 

These  latter  remarks  apply  in  full  force  to  the  specimens  of  this  inter- 
esting species  as  it  occurs  in  Central  Nevada.  Here  it  has  the  same  asso- 
ciations and  is  of  the  same  geologic  age.  It  has  not  been  discovered,  as 
far  as  known,  in  the  interval  of  1,600  miles  between  its  former  known  west- 
ern extension  in  the  State  of  Indiana  and  the  present  limit.  This  is,  how- 
ever, largely  due  to  the  few  localities  where  the  Devonian  rocks  are  ex- 
posed to  examination,  and  the  fact  that  the  great  mass  of  Paleozoic  strata 
west  of  the  Mississippi  Valley  have  been  but  partially  examined  by  the  geolo- 
gist, and  paleontologic  investigation  has  been  the  result  of  hasty  collecting 
rather  than  a  systematic  study  of  the  fauna  of  any  locality  or  horizon. 

Formation  and  locality. — Upper  Devonian  limestone,  Eureka  District, 
Nevada. 

Genus  CONULAKIA  Miller. 

Conularia  (sp.  undt.). 

A  single  fragment  was  found  in  the  lower  beds  at  Comb's  Peak,  but 
not  in  a  condition  to  determine  its  specific  relations. 


FOSSILS  OF  THE  DEVONIAN. 


Genus  HYOLITHES  Eichwald. 


199 


Hyolithes,  sp.  (?) 
Plate  vi,  figs.  8,  8 a. 

Form  elongate,  triangular,  tapering  regularly  and  gradually  to  an  acute 
extremity.  Transverse  section  subtriangular,  slightly  convex  on  the  ventral 
side.  Dorsal  angle  obtuse.  Breadth  and  depth  as  two  to  one.  Ventral  face 
gently  convex,  arching  slightly  from  the  apex  to  the  aperture  Dorsal  face 
with  a  longitudinal  concavity  about  equal  to  the  convexity  of  the  ventral 
face;  strongly  arched  transversely.  The  aperture  is  not  preserved,  but  was 
probably  oblique,  as  in  allied  species. 

Surface  of  shell  unknown,  as  the  only  two  specimens  obtained  are  in 
the  form  of  casts.  This  species  is  very  closely  allied,  if  not  identical,  in 
general  form  with  Hyolitlies  aclis  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  1JJ1?,  pi. 
xxxii,  figs.  22-30;  pi.  xxxii  A,  figs.  23-25)  from  the  Hamilton  Group  of  New 
York  The  finding  of  specimens  preserving  the  shell  may  show  differences 
that  are  not  now  apparent,  and  for  this  reason  no  specific  identification  is 
attempted. 

Professor  Hall  calls  attention  to  the  small  number  of  species  of  Hyo- 
lithes in  American  Paleozoic  strata  as  compared  with  other  Paleozoic  coun- 
tries, and  also  the  limited  geographic  range  of  the  American  species.  All 
the  collections  made  during  the  past  few  years  from  the  Paleozoic  formations 
of  the  Rocky  Mountains  and  westward  have  offered  no  new  well-determined 
forms,  and  but  one  species  is  known  at  present  from  above  the  Cambrian, 
or  first,  fauna  Owing  to  the  restricted  range  of  the  Devonian  species  of 
New  York,  we  hesitate  to  identify  this  species  with  H.  aclis,  or  to  define  it  as 
a  new  species,  until  better  specimens  are  collected. 

Formation  and  locality. — Lower  Devonian  of  Atrypa  Peak,  Eureka  Dis- 
trict, Nevada. 

Genus  COLEOLUS  Hall. 

Coleolus  laevis,  n.  sp. 

Plate  vi,  fig.  9. 

Shell  an  extremely  elongate,  cylindro-conical,  straight  or  slightly 
curved  tube  ;  section  circular. 


200  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Surface  of  both  the  inner  and  outer  walls  smooth. 

Dimensions:  the  largest  tube  obtained  has  a  length  of  llmia  and  a 
diameter  of  0.5mm. 

This  species  is  closely  allied  to  Coleoprion  f  Bohemicum  Barrande  (Syst. 
Sil.  Boheme.,  vol.  iii,  p.  109,  pi.  xv,  fig.  15)  from  the  Upper  Silurian  of  Bo- 
hemia. 

The  surface  characters  of  the  Bohemian  specimen  are  unknown,  and 
we  would  hesitate  in  identifying  a  species  of  this  character  from  the  sum- 
mit of  the  Devonian  in  Nevada  with  one  from  the  Silurian  of  Bohemia  even 
if  more  was  known  of  each  than  is  at  present 

The  Nevada  species  was  gregarious,  the  little  slender  tubes  now  lying 
thickly  in  the  shale;  some  of  them  have  a  smooth,  shining  surface.  The 
shell  is  rather  thick. 

Formation  and  locality. — Upper  Devonian,  White  Pine  shale,  on  the 
south  slope  of  Diamond  Peak,  Eureka  District,  Nevada. 


CEPHALOPODA. 
Genus  ORTHOCERAS  Breynius. 

Five  species  of  Orthoceras  are  recognized  among  the  numerous  frag- 
ments from  the  lower  horizon  of  the  Devonian  limestone.  None  of  them, 
however,  are  sufficiently  represented  to  be  characterized  as  specifically  dis- 
tinct from  described  species,  and  their  further  determination,  beyond  a  note 
of  the  characters  of  each,  is  deferred  until  more  and  better  material  is  col- 
lected. 

I.  Shell  robust,  straight,  elongate.  Transverse  section  circular  in  un- 
compressed specimens.  Apical  angle  about  15°,  measuring  the  septate 
portion.  Chamber  of  habitation  and  initial  point  unknown.  Air-chambers 
numerous  and  shallow,  having  a  depth  of  about  5mm  where  the  diameter  is 
25mm.  Septa  thin,  the  concavity  equal  to  the  interspaces.  Sutures  gently 
curved,  but  not  oblique  to  the  axis.  Siphuncle  central;  small  at  its  inser- 
tion in  the  septa;  its  passage  through  the  interseptal  spaces  has  not  been 
observed.  Test  removed  from  all  observed  specimens.  There  is  a  large 


FOSSILS  OF  THE  DEVONIAN. 


201 


fragment  45mm  in  diameter,  preserving  three  air-chambers,  that  is  closely 
related  to  this  form;  the  concavity  of  the  septa  is  much  greater,  being  15mm. 
In  some  respects  these  fragments  are  allied  to  Orthoceras  Bebryx  Hall 
(Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  275),  of  the  Hamilton  and  Chemung  Groups  of 
New  York,  but  appear  to  belong  to  a  distinct  species. 

II.  This  is  a  more  slender  form  than  the  preceding,  and  diminishes  less 
rapidly  in  receding  from  the   chamber  of  habitation.     Transverse  section 
circular.     Apical  angle,  5°  to  6°.     Chamber  of  habitation  large,  without  any 
constriction  as  far  as  observed.     Air-chambers  numerous,  having  a  depth  of 
3mm  where  the  diameter  of  the  tube  is  13mm.     Septa  thin,  the  concavity 
equal  to  a  little  less  than  the  interspaces.     Sutures  transverse,  straight. 

The  best  preserved  specimen  is  60mm  in  length,  with  a  diameter  at  the 
septate  end  of  llmm,  near  the  mouth  of  the  chamber  of  habitation  of  16mm, 
the  chamber  of  habitation  having  a  length  of  35mm.  Surface  characters  un- 
known. This  form  is  related  to  Orthoceras  exile  Hall  (Pal.  N.  Y.,  vol.  v, 
pt.  2,  p.  290),  of  the  Hamilton  Group  of  New  York. 

III.  This  fragment  has  three  septa  in  a  length  of  25mm;  transverse  sec- 
tion slightly  ovate,  as  8  to  9 ;  greatest  diameter,  27mm.     Apical  angle  about  5°. 
Septa  thin,  with  a  concavity  equal  to  the  depth  of  the  chambers     Siphuncle 
eccentric,  distant  from  the  nearest  point  on  the  walls  of  the  air-chambers 
about  two-fifths  the  greatest  diameter  of  the  tube.     The  "diameter  at  the 
septa  is  2mm,  where  the  major  diameter  of  the  tube  is  18mm. 

The  greater  depth  of  the  air-chambers  and  the  eccentric  position  of  the 
siphuncle  distinguish  this  from  the  preceding  form. 

IV.  Several  small  fragments  of  an  annulated  species  occur  that  are  not 
unlike  portions  of  small  specimens  of  Ortlioceras  Thoas  Hall  (Pal.  N.  Y.,  vol. 
v,  pt.  2,  p.  261),  of  the  Upper  Helderberg  Group.     A  specimen  7mm  in 
diameter  has  seven  annulations  in  a  distance  of  21mm.     Septa  and  siphuncle 
not  observed. 

V.  Large  annulated  form,  30mm  in  diameter.     Annulations  narrow,  de- 
pressed, with  a  broad,  slightly-depressed  area  between  them,  five  annula- 
tions in  a  distance  of  30mm.     The  margins  of  the  septa  appear  about  midway 
between  the  annotations. 


202  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

There  are  also  a  number  of  elongate,  slender  tubes,  the  relations  of 
which  have  not  been  determined.  They  are  probably  the  young  of  one  of 
the  smooth-tubed  forms. 

Formation  and  localilities. — Devonian  limestone;  Comb's  Peak  and  Lone 
Mountain,  Eureka  District,  Nevada. 


Genus  GOMPHOCERAS  Sowerby. 

Gomphoceras  suboviforme,  n.  sp. 
Plate  xvii,  figs.  8,  8  a. 

Shell  small,  subglobose,  attenuated  towards  the  apex  from  the  last 
chamber.  Transverse  section  subcircular.  The  point  of  greatest  transverse 
section  of  the  grand  chamber  is  a  little  anterior  to  the  last  septum.  Tube 
expanding  regularly,  with  the  sides  nearly  straight  up  to  the  chamber  of 
habitation,  where  it  is  somewhat  inflated.  Chamber  of  habitation  rather 
large,  with  the  slightly  convex  ventral  and  lateral  faces  sloping  gradually 
to  the  apertural  extremity,  while  the  dorsal  face,  which  is  gently  concave 
above  the  zone  of  greatest  transverse  section,  is  at  right  angles  to  the  plane 
of  the  last  septum. 

Air-chambers  numerous,  regular,  not  perceptibly  increasing  in  depth 
from  where  the  tube  is  10mm  in  diameter  to  the  chamber  of  habitation; 
average  depth  nearly  2mm,  or  ten  chambers  in  a  distance  of  1 9mm.  Sutures 
straight  and  horizontal.  Siphuncle  small,  situated  near  the  ventral  margin; 
diameter  2mm,  where  the  ventro-dorsal  diameter  of  the  tube  is  17mm;  its 
structural  elements  are  unknown,  as  the  cast  shows  only  the  diameter. 

•/ 

Internal  mold  of  the  tube  apparently  smooth.  Length  of  chamber  of  habi- 
tation (grand  chamber),  18mm;  greatest  diameter,  24mm;  length  of  tube,  em- 
bracing ten  air-chambers,  19mm;  anterior  diameter  of  last  chamber,  22mm;  of 
first  apical  chamber  preserved  in  the  specimen,  10mm. 

This  species  is  distinguished  from  G.  oviforme  Hall  (Pal.  N.  Y.,  vol.  v, 
pt.  2,  p.  344)  of  the  Upper  Helderberg  Group  of  New  York,  by  the  more 
attenuated  and  less  ovate  form,  and  the  uniform  and  more  shallow  cham- 
bers. It  also  resembles  G.raphanus  Hall  (loc.  cit.,  p.  347),  of  the  Hamilton 


FOSSILS  OF  THE  DEVONIAN. 


203 


Group.     The  latter  is  more  slender,  and  has  a  less  gibbous  chamber  of  habi- 
tation. 

Formation  and  locality. — Upper  horizon  of  the  Devonian  limestone;  The 
Gate,  northwest  of  Eureka,  Eureka  District,  Nevada. 

Genus  CYRTOCERAS  Goldfuss. 

Cyrtoceras  Nevadense,  n.  sp. 

Plate  xvii,  figs.  7,  7  a. 

This  species  is  represented  by  a  portion  of  the  chambered  tube  SO"1111 
in  length ;  the  apical  extremity,  beyond  a  diameter  of  1  Omm,  and  the  cham- 
ber of  habitation  having  been  broken  away. 

Shell  small,  regularly  curved,  the  depth  of  the  arc  of  curvature  being 
2mm  in  a  length  of  30mm.  Transverse  section  subcircular.  Apical  angle  of 
the  lateral  faces  about  10°.  Air-chambers  numerous,  varying  in  depth  from 
2mm  to  3mm  in  a  distance  of  30mm,  the  larger  extremity  having  a  depth  of 
1 7mm  and  the  apical  section  of  1  Omm.  Septa  smooth,  with  a  concavity  a  little 
less  than  the  depth  of  the  air-chambers.  Sutures  horizontal,  with  a  slight 
backward  curvature  on  the  dorsal  side.  Siphuncle  central.  Test  thin. 

Surface  marked  by  lines  of  growth  that  have  a  somewhat  obtuse  sinus 
on  the  ventral  side.  The  internal  mold  preserves  a  trace  of  the  exterior 
markings  of  the  test. 

This  species  resembles  Cyrtoceras  (  Gomphoceras)  metula  Hall  (Pal.  N.  Y., 
vol.  v,  pt.  2,  p.  360),  of  the  Upper  Helderberg  Group  of  New  York.  It 
differs  in  the  central  position  of  the  siphuncle,  apical  angle,  and  curvature 
of  the  sutures. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  Eureka  District,  Nevada. 


Genus  GONIATITES  De  Haan. 

Goniatites  desideratus,  n.  sp. 
Plate  xvii,  fig.  10. 

Shell  discoid;  estimating  from  the  depth  of  the  umbilicus,  the  thick- 
ness of  the  disk  is  about  10mm.     There  were  probably  four  volutions;  two 


£04  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

are  preserved  in  the  specimen  before  us,  with  a  third  partially  shown  ;  the 
outer  ones  embrace  but  little  of  the  inner;  they  are  somewhat  flattened  and 
apparently  sharply  rounded  on  the  ventral  lobe.  Umbilicus  wide,  exposing 
all  the  inner  volutions.  The  volutions  enlarge  very  gradually  until  towards 
the  outer  portion  of  the  last  volution,  or  the  grand  chamber,  where  the  ex- 
pansion is  slightly  increased. 

The  entire  dimensions  of  the  chamber  of  habitation  are  unknown,  as  a 
portion  is  broken  away  and  the  latter  septa  are  partially  concealed  by  the 
test ;  the  part  remaining,  however,  indicates  that  it  was  large.  Four  septa 
are  seen  on  the  outer  volution,  obtained  by  cutting  away  a  portion  of  the 
test ;  they  are  thin  and  uniform,  curving  a  little  forward  on  the  umbilical 
margin  and  then  gently  curving  backward,  including  a  single  broad,  flat- 
tened lobe  which  occupies  the  entire  width  of  the  volution.  Ventral  lobe 
unknown.  Test  thin. 

Surface  marked  by  strong  striae  and  lines  of  growth  that  curve  forward 
from  the  umbilicate  lobe,  crossing  the  direction  of  the  septa  at  an  acute  an- 
gle near  the  umbilical  margin  and  nearly  at  right  angles  on  the  outer  por- 
tion of  the  volution. 

This  species  differs  in  its  wide  umbilicus  united  with  the  direction  of 
the  surface  striae  and  septa  from  any  form  that  has  come  within  our  obser- 
vation. 

Formation  and  locality. — Devonian  limestone,  Comb's  Peak,  Eureka 
District,  Nevada. 

CRUSTACEA. 

Genus  BEYRICHTA  McCoy. 

Beyrichia  (Primitia)  occidentalis,  n.  sp. 

Plate  xvii,  figs.  4,  4  a. 

Carapace  large,  Leperditia-like  in  outline,  4  5mm  in  length  by  2.75mm  in 
breadth ;  strongly  convex ;  dorsal  margin  slightly  incurved  two-thirds  the 
length  of  the  valves  and  terminating  anteriorly  and  posteriorly  in  obtuse 
angles  formed  by  its  union  with  the  anterior  and  posterior  margins ;  ventral 
margin  gently  curved  to  its  union  with  the  broadly  rounded  anterior  and 
posterior  margins.  Two  deep  and  slightly  curved  sulci  penetrate  the  cen- 


FOSSILS  OF  THE  DEVONIAN.  205 

tral  dorsal  region  of  the  valve,  terminating  about  three-fifths  the  distance 
across  the  valve  from  the  dorsal  margin;  the  posterior  sulcus  is  narrow  and 
curves  backward,  while  the  anterior  is  quite  broad,  with  a  forward  curve, 
each  having  its  origin  on  the  dorsal  margin  as  a  faint  groove  and  deepening, 
with  the  convexity  of  the  valve ;  this,  united  with  the  opposite  curvature 
of  the  sulci,  forms  an  elongate  lobe  or  tubercle  on  the  central  dorsal  portion 
of  the  valve ;  on  casts  of  the  carapace,  and  on  valves  where  the  two  sulci 
are  united  by  a  slight  sulcus  at  their  lower  termination,  the  size  and  appear- 
ance of  the  tubercle  is  greatly  increased;  a  shallow  groove  occurs  just  within 
the  anterior  and  posterior  dorsal  angles  and  extends  a  short  distance  down 
the  anterior  and  posterior  margins,  where  it  becomes  obsolete;  two  small, 
elongate  nodes  are  situated  near  the  dorsal  margin,  each  a  little  within  the 
anterior  and  posterior  dorsal  groove  respectively ;  the  surface  of  the  nodes, 
the  central  lobe,  and  margins  of  the  sulci  are  smoothly  and  evenly  rounded. 

Surface  finely  granulated,  the  granules  arranged  along  minute,  irreg- 
ular striae,  or  lines  that  radiate  from  the  outer  margins  of  the  sulci  to  the 
anterior,  posterior,  and  ventral  margins. 

The  presence  of  the  two  sulci,  as  seen  in  all  the  adult  individuals, 
properly  refers  this  species  to  the  genus  Beyrichia.  A  study  of  a  series  of 
specimens,  however,  that  pass  from  the  largest  size  down  to  individuals 
lmm  in  length,  shows  that  the  posterior  sulcus  becomes  more  obscure  with 
the  decrease  in  size  of  the  individual,  and  that  when  the  shell  is  lmm  in  length 
the  posterior  sulcus  is  obsolete  and  a  true  unisulcate  Beyrichia  results  that 
may  be  referred  to  the  genus  Primitia  (plate  xvii,  fig.  4  a).  The  adult  is  a 
member  of  the  corrugate  group  of  Beyrichise,  of  which  Beyrichia  Wilckensiana 
Jones  (Ann.  and  Mag.  Nat.  Hist,  2d  ser.,  vol.xvi,  p.  83,  pi.  v,  figs.  17, 18, 1855) 
is  the  type,  and  the  young  form,  of  the  "Sirnplices"  of  which  B.  (Primitia) 
strangulata  (Salter)  Jones  (Ann  and  Mag.  Nat.  Hist,  2d  ser.,  vol.  xvi,  p.  17 1, 
pi.  vi,  fig.  18,  1855;  Ibid.,  3d  ser.,  vol.  xvi,  p.  416,  1865),  or  B.  (Primitia) 
simplex  Jones  (Quart.  Jour.  Geol.  Soc.,  vol.  ix,  p.  161,  pi.  vii,  fig.  7)  is  the  type. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone; 
Newark  Mountain,  Eureka  District,  and  Lone  Mountain,  18  miles  north- 
west of  Eureka,  Nevada. 


206  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

In  the  collections  from  the  White  Pine  District,  this  species  is  found 
in  the  Upper  Devonian  of  Telegraph  Peak.  The  specimens  all  belong  to 
the  smaller  variety  in  which  the  double  sinus  is  almost  obsolete. 


Genus  LEPERDITIA  Roualt. 

Leperditia  rotundata,  n.  sp. 
Plate  xvi,  fig.  5. 

Carapace  of  medium  size,  5mm  in  length  by  3.5mm  in  breadth;  convex, 
subovate  in  outline,  with  the  anterior  extremity  a  little  narrower  than  the 
posterior;  dorsal  margin  straight,  about  five-sixths  the  length  of  the  valves; 
it  terminates  anteriorly  and  posteriorly  in  simple  or  slightly  produced 
angles  formed  by  its  union  with  the  anterior  and  posterior  margins  respect- 
ively; anterior  and  posterior  margins  broadly  rounded;  ventral  margin 
regularly  curved  and  on  the  right  valve  turned  under,  forming  a  rounded 
ventral  edge  to  the  carapace;  ventral  valve  proportionally  narrower  than 
the  right,  and  terminating  in  a  plain  edge  on  the  ventral  margin. 

The  uniform  convexity  of  the  surface  is  broken  on  the  anterior  and 
posterior  dorsal  angles  by  a  slight  groove  just  within  the  margin,  and  on 
the  anterior  dorsal  region  by  a  faintly-defined  sulcus,  indicating  the  position 
of  the  depressed  eye-tubercle ;  muscular  scar  a  little  posterior  to  the  center 
of  the  valve,  as  shown,  on  a  large  right  valve,  by  its  having  a  lighter  color 
than  the  carapace. 

Surface  smooth  to  the  e'ye,  but  minutely  punctate  under  a  strong 
magnifying  glass. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone; 
southeast  of  Richmond  Mountain,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  DEVONIAN. 


207 


PCECILOPODA. 
Genus  PHACOPS  Emmerich. 

Phacops  raua  Green  (Sp.). 
Calymene  bufo,  var.  rana  Green,  1832.     Monograph  Trilobites  North  America,  p.  42. 
Phacops  rana  Hall,  1861.    Desc.  New  Species  of  Fossils,  etc.,  p.  65.    Idem.,  1862.    Fif- 
teenth Ann.  Kep.  N.  Y.  State  Cab.  Nat.  His.,  p.  93. 
Meek  &  Wortheu,  1868.     Geol.  Surv.  111.,  vol.  iii,  p.  447,  pi.  ii,  figs.  la-e. 
Nicholson,  1873.     Pal.  Prov.  Ontario,  p.  123,  fig.  5,  6  a. 
Hall,  1876.     Pal.  N.  Y.,  Illustrations  of  Devonian  Fossils,  Crustacea,  pi. 

vii,  figs.  1-11;  pi.  viii,  figs.  1-17. 

Whitfiekl,  1883.    Geol.  Wisconsin,  vol.  iv,  p.  330,  pi.  xxvii,  figs.  17-19. 
Compare  Phacops  bombifrons  Hall.    Pal.  N.  Y".,  Illustrations  Devonian  Fossils,  Crus- 
tacea, pi.  vi,  figs.  18-29. 

A  comparison  of  specimens  from  the  Hamilton  Group  of  New  York 
with  those  from  Nevada  shows  variations  that  are  quite  strongly  marked, 
but  which  are  scarcely  of  specific  importance,  if  we  consider  that  the  east- 
ern form  is  imbedded  in  a  shale  and  more  or  less  compressed,  while  the 
Nevada  examples  are  in  a  limestone,  and  have  also  undergone  slight 
changes  resulting  from  the  differences  in  their  original  habitat  as  compared 
with  the  New  York  specimens.  The  glabella  of  the  Nevada  form  is  more 
inflated  and  protruded  in  front,  a  narrow  furrow  occurs  between  it  and  the 
eye,  and  the  entire  head  is  much  more  convex,  but  in  one  or  two  specimens 
these  characters  are  reduced  and  a  typical  head  of  Pliacops  rana  is  shown. 
The  species  as  seen  in  most  of  the  specimens  resembles,  in  its  prominent  gla- 
bella marked  in  the  cast  by  the  little  elevations  that  filled  the  hollows  of 
the  pustules  seen  in  the  outer  surface  of  the  dorsal  shell,  Phacops  lombifrons, 
and  appears  to  be  a  species  uniting  the  latter  and  Phacops  rana. 

Formation  and  localities. — Lower  horizon  of  the  Devonian  limestone; 
Comb's  Peak  and  other  localities  in  the  Eureka  District;  also  at  Lone 
Mountain,  18  miles  northwest  of  Eureka,  Nevada. 


Genus  DALMANITES  Emmerich.13 

Dalmanites  Meeki,  n.  sp. 

Plate  xvii,  figs.  5,  5a-c. 

Dalmanites  (undt.  sp.)  Meek,  1877.     Geol.  Expl.  Fortieth  Parallel,  vol.  iv,  p.  48,  pi.  ir 

figs.  11,  11  a. 
The  general  form  and  the  characters  of  the  thorax  are  unknown,  the 


208  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

description  of  the  species  being  based  on  portions  of  the  cephalic  shield  and 
entire  specimens  of  the  pygidium. 

The  glabella  is  subclavate,  moderately  convex,  and  separated  from  the 
fixed  cheeks  by  a  well-defined  furrow;  anterior  lobe  composing  more  than 
half  of  its  entire  area,  transversely  subovate,  the  length  being  two-thirds  of 
the  width;  lateral  furrows  distinctly  defined,  deepest  at  the  inner  end;  the 
anterior  furrow  extends  obliquely  forward  and  the  two  posterior  pairs  have 
a  slight  inclination  backward ;  this  gives  to  the  anterior  lateral  lobe  a 
narrow  base  and  wider  terminal  portion,  or  a  subtrigonal  form  to  the  lobe; 
the  two  posterior  lobes  are  shorter  and  with  their  sides  subparallel  to  each 
other.  Occipital  segment  slightly  rounded,  almost  flat  on  the  upper  portion 
in  the  cast,  broadest  at  the  center,  narrowing  slightly  towards  the  dorsal 
furrows;  occipital  furrow  strongly  defined,  arching  a  little  forward  at  the 
center.  Fragments  of  the  fixed  cheeks  and  palpebral  lobe,  with  a  free 
cheek  found  associated  with  them,  show  a  large  reniform  eye  situated  oppo- 
site the  anterior  lateral  lobe  of  the  glabella  with  a  deep  furrow  extending 
around  its  base;  the  slope  from  the  eye  to  the  shallow  marginal  groove  is 
quite  abrupt  and  gives  considerable  convexity  to  the  head;  the  outer  margin 
is  of  medium  width,  with  a  gentle  slope  outward. 

Hypostoma  subtriangular,  as  wide  anteriorly  as  long,  moderately  con- 
vex; anterior  margin  gently  curved;  lateral  margins  contract  quite  rapidly 
at  the  anterior  lateral  angles  and  then  converge  regularly  to  the  posterior 
extremity,  where  they  converge  very  abruptly,  forming  an  obtuse  point 
which  has  several  short  spines  or  points  along  its  lateral  margins;  a  sulcus 
that  rises  on  the  lateral  margin  curves  backward,  and  unites  with  its  fellow 
at  the  center  three-fourths  the  distance  from  the  anterior  to  the  posterior 
extremity;  a  broad  shallow  groove  crosses  anterior  and  subparallel  to  this, 
giving  a  lobed  appearance  to  the  posterior  half  of  the  hypostoma. 

Thorax:  A  cast  of  a  single  segment  is  all  that  occurs  associated  with  the 
other  parts  of  this  species;  the  median  lobe  is  moderately  convex  and 
nearly  transverse;  lateral  lobe  curves  outward* and  a  little  backward,  ter- 
minating in  a  rather  abrupt  point;  pleural  groove  deep,  crossing  the  seg- 
ment obliquely  from  the  anterior  margin  to  the  posterior  outer  angle. 

13Dalmania,  Emmerich,  1845;  modified  by  Barraude  to  Dalmanites  in  1852. 


FOSSILS  OF  THE  DEVONIAN. 


209 


Pygidium  moderately  convex,  sub  trigonal  in  outline;  length  two- thirds 
of  the  width;  ancerior  lateral  angles  a  little  rounded,  lateral  margins  con- 
verge with  a  slight  outward  curve  to  the  base  of  a  strong  upward-curving 
spine  that  forms  the  posterior  extremity  of  the  pygidum,  the  spine  curving 
up  at  an  angle  of  45°  in  adult  specimens  and  from  35°  to  25°  in  the  younger 
individuals;  median  lobe  less  convex  than  the  lateral  lobes  and  two-thirds 
as  wide,  uniformly  rounded,  and  tapering  gradually  to  the  posterior  extrem- 
ity; marked  by  13  to  15  well-defined  annulations  and  an  elongate  terminal 
ring;  lateral  lobes  with  10  to  11  strongly  defined  ribs  that  curve  in  their 
outer  half  obliquely  backward,  terminating  just  within  the  narrow  margin. 

Surface  of  the  glabella,  thoracic  segments,  and  pygidium  punctate. 

This  is  the  largest  trilobite  }7et  discovered  in  the  Devonian  of  the  West. 
Individuals  35cm  in  length  are  indicated  by  the  larger  fragments,  and  one 
hypostoma  is  7cm  in  length. 

The  pygidium  resembles  that  of  Dalmanites  micrurus  of  the  Lower 
Helderberg-  limestone  of  New  York  (Pal.  N.  Y.,  vol.iii,  p.  359,  plate  Ixxiv,  figs. 
13-20),  but  differs  in  the  less  number  of  annulations  in  the  lobe  and  in  the 
punctate  surface.  To  D.  anchiops  Green  (sp.)  (Pal.  N.  Y.,  Illustrations  of 
Devonian  Fossils,  Crustacea,  pi.  ix)  of  the  Upper  Helderberg  limestone  of 
New  York,  it  has  a  strong  resemblance  when  compared  to  young  individ- 
uals, but  differences  exist  that  readily  separate  the  species. 

The  late  Mr.  F.  B.  Meek  described  and  illustrated  fragments  of  an 
unknown  form  of  Dalmanites,  from  the  Devonian  limestone  of  the  Pinon 
Eange  of  Central  Nevada,  and  the  two  pygidise  illustrated  are  closely  related 
to  those  from  the  Eureka  District,  the  character  of  the  surface,  which  is 
smooth  or  granulose,  as  seen  in  badly  weathered  specimens,  alone  appear- 
ing to  be  different. 

The  specific  name  is  given  as  a  slight  recognition  of  Mr.  Meek's  ex- 
tended and  valuable  contributions  to  our  knowledge  of  the  invertebrate 
Paleontology  of  the  Western  United  States. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone, 
Comb's  Peak,  and  on  the  divide  at  the  head  of  the  Reese  and  Berry  Cafion, 
Eureka  District,  Nevada. 
14  c  D  w 


210  PALEONTOLOGY  OF  THE  EUBEKA  DISTRICT. 


Dalmanites  (nndt.  sp.). 

At  Comb's  Peak  a  small  and  very  perfect  glabella  of  a  species  of  Dal- 
manites was  found.  It  is  quite  distinct  from  the  associated  Dalmanites  Meeki, 
as  the  surface  is  finely  granulose  with  larger  granules  irregularly  inter- 
spersed ;  the  determination  of  its  specific  relations  is  left  until  more  material 
can  be  obtained. 

Genus  PEOETUS  Steininger. 
Froetus  Haldemani  Hall. 

Proetus  Haldemani  Hall,  1861.  Descriptions  of  New  Species  of  Fossils,  etc.,  p.  74. 

Haldemani  Hall,  1862.  Fifteenth  Ann.  Kep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  102. 

Haldemani  Hall,  1876.  Pal.  N.  Y.,  Illustrations  of  Devonian  Fossils,  Desc. 
pi.  xxi,  tigs.  7,  8,  9. 

Of  this  species  the  glabella  and  pygidium  were  alone  obtained.  The 
glabella  varies  from  that  of  Proetus  Haldemani  in  being  more  compressed 
and  the  pygidium  in  having  one  or  two  less  annulations  in  the  median  lobe; 
otherwise  they  appear  to  be  identical. 

Formation  and  locality. — Devonian  limestone,  Rescue  Hill,  west  side  of 
Rescue  Canon,  Eureka  District,  Nevada. 

Proetus  margiiialis  Conrad  (Sp.). 

Calymene  marginalis  (?)  Conrad,  1839.    Ann.  Eep.  Pal.  N.  Y.,  p.  66. 

Proetus  marginalis  Hall,  1861.    Descriptions  of  New  Species  of  Fossils,  etc.,  p.  76. 

marginalis  Hall,  1862.    Fifteenth  Ann.  Rep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  104. 

marginalis  Hall,  1876.    Pal.  N.  Y.,  Illustrations  of  Devonian  Fossils,  Crustacea, 
pi.  xxi,  figs.  24-28. 

We  fail  to  discover,  on  a  direct  comparison  of  specimens  of  Proetus 
marginalis,  from  the  Tully  limestone  of  New  York  and  entire  specimens 
from  Comb's  Peak,  any  characters  that  would  warrant  the  separation  of 
the  latter  as  a  distinct  species.  The  most  prominent  variation  is  in  the 
width  and  outline  of  the  border  of  the  head,  but  on  examining  the  figures 
given  by  Professor  Hall,  on  plate  xxi  (Illustrations  of  Devonian  Fossils), 
quite  as  wide  a  variation  is  shown  between  figs. .25  and  26  as  between  indi- 
viduals from  New  York  and  Nevada.  Continuing  the  comparison  with 


FOSSILS  OF  THE  DEVONIAN. 


Ill 


New  York  specimens  of  the  genus,  P.  clarus,  Hall,  of  the  same  work,  plate 
xx,  fig.  12,  is  nearly  identical  with  the  Nevada  form,  its  greater  width  and 
less  convexity  distinguishing  it,  also  a  slight  difference  in  the  details  of 
the  border  of  the  head,  features  that  in  many  species  of  the  genera  Caly- 
mene,  Asaphus,  etc.,  are  not  of  specific  importance  unless  very  strongly 
marked. 

Formation  and  locality. — Lower  horizon  of  the  Devonian  limestone; 
Comb's  Peak,  Eureka  District,  Nevada. 

Genus  PHILLIPSIA  Portlock. 
Phillipsia  coronata  Hall  f 

Phillipsia  f  (Bracliymetopus  f)  ornata  Hall,  1876.    Pal.  N.  Y.,  Illustrations  of  Devonian 

Fossils,  Crustacea,  pi.  xxi,  fig.  1  (Nat.  P.  ornata  Portlock  1843). 
coronata  Hall,  1877.    Cat.  Amer.  Pal.  Foss.,  Miller,  p.  221. 

The  central  portion  of  the  head  is  alone  preserved  in  the  specimen 
from  Nevada ;  lateral  compression  has  distorted  its  outline  and  convexity 
so  that  the  comparison  with  the  fragment  -from  the  Hamilton  Group  of 
New  York,  in  which  the  glabella  and  frontal  border  is  preserved,  is  neces- 
sarily imperfect,  but  from  the  close  relations  of  the  two,  the  species  from 
Newark  Mountain  is  for  the  present  referred  to  Phillipsia  coronata. 

Formation  and  locality. — Middle  horizon  of  the  Devonian  limestone; 
Newark  Mountain,  Eureka  District,  Nevada. 


SUPPOSED  EGGS  OF  THE  TRILOBITE. 

Numerous  small,  spheroidal  bodies,  one-half  a  millimeter  in  diameter, 
occur  in  the  Devonian  limestone  of  Lone  Mountain  in  association  with  the 
iragmentary  remains  of  Phacops  rana,  Proetus  marginalis,  and  Dalmanites 
Meeki.  In  appearance  they  resemble  the  forms  illustrated  by  M.  Barrande,14 
which  he  considers  the  eggs  of  the  trilobite.  A  careful  examination  does 
not  lead  me  to  make  any  other  reference  of  them,  as  they  answer  very 
closely  to  what  I  would  conceive  as  the  ova  of  the  trilobite,  and  their 
association  with  the  remains  of  trilobites  also  favors  this  view. 

"Syst.  Sil.  BohSme,  p.  270,  vol.  i,  Trilobites,  pi.  xxvii,  figs.  1-3,  1852. 


FOSSILS  OF  THE  CARBONIFEROUS. 

A  list  of  all  the  species  known  to  occur  in  the  Carboniferous  formation 
of  the  Eureka  District  is  given  in  the  systematic  catalogue  at  the  end  of 
this  report,  and  only  the  rarer  forms  and  new  species  are  mentioned  in 
the  text.  In  some  instances  a  species  is  partially  identified  by  fragments, 
in  which  case  the  similarity  to  the  described  species  is  mentioned  in  the  cat- 
alogue. 

ECHINODERMATA. 

Of  this  class,  representatives  of  the  Echinidea  were  obtained  in  the 
spines  of  two  species,  and  of  the  Crinoidea  in  numerous  segments  of  the 
columns  of  several  species.  As  a  whole  the  class  is  very  imperfectly  repre- 
sented in  the  central  portions  of  the  Rocky  Mountain  area,  and  with  the  ex- 
ception of  a  few  species  from  Montana  and  New  Mexico  the  great  Crinoidal 
fauna  of  the  Lower  Carboniferous  limestones  of  the  Mississippi  Valley  is 
unknown  in  the  Rocky  Mountains.  A  further  examination  of  the  Lake 
Valley  District  in  New  Mexico,  however,  will  undoubtedly  add  largely  to 
the  knowledge  of  the  distribution  of  the  Crinoidal  fauna,  as  several  species 
from  there  are  identical  with  those  from  the  Burlington  limestone. 

Since  the  above  was  written  Mr.  F.  Springer  (Amer.  Jour.  Sci.,  vol.  xxvii, 
p.  97,  1883),  has  described  a  large  and  varied  fauna  from  the  Lake  Valley 
District. 

Genus  AKdLEOClDARIS  McCoy. 

Archaeocidaris,  sp.  ? 

Two  species  are  represented  by  the  spines.     One  is  very  much  like  A. 

Wortheni  Hall  (Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  700,  1858),  and  the  other 
212  t 


FOSSILS  OF  THE  CARBONIFEKOUS. 


213 


approaches  A.  Shumardana  Hall  (Ibid.,  p.  699)  of  the  Lower  Carboniferous 
limestone. 

Formation  and  locality. — Lower  portion  of  the  Lower  Carboniferous 
limestone  on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


BRACHIOPODA. 

Genus  DISCINA  Lamarck. 
Discina  Newberryi  Hall. 
Plate  xviii,  figs.  3  (2,  2  a?). 

Discina  newberryi  Hall,  1863.     Sixteenth  Ann.  Kep.  N.  Y.  State  Cab.  Nat.  Hist.,  p.  30. 

Pal.  N.  Y.,  1867,  vol.  iv,  p.  25,  pi.  i,  figs.  10 a,  &,  lla-c. 
Discina  ( Orbiculoidea)  Newberryi  Meek,  1875.   Pal.  Ohio,  vol.  ii,  p.  277,  pi.  xiv,  figs.  1  a-d. 

The  Eureka  shells  present  no  features  by  which  they  can  be  distin- 
guished from  this  species  when  directly  compared  with  authentic  specimens 
from  the  Waverly  sandstones  of  Ohio. 

At  a  little  lower  horizon  a  form  of  Discina  occurs  in  a  black  shale  that 
may  belong  to  this  species.  All  the  specimens  are  more  or  less  distorted 
by  pressure.  The  two  valves  are  shown  by  figs.  2,  2  a  of  plate  xviii. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
Richmond  Mountain  and  on  east  slope  of  a  small  conical  hill  on  the  east 
side  of  Secret-canon-road  Canon,  Eureka  District,  Nevada. 


Discina  nitida  Phillips. 
Plate  vii,  figs.  4,  4  a. 

Orbicula  nitida  Phillips,  1836.    Geol.  of  Yorkshire,  pt.  2,  p.  221,  pi.  xi,  figs.  10-13. 
Discina  Missouriensis  Shumard,  1860.    Trans.  St.  Louis  Acad.  Sci.,  vol.  i,  p.  221  (as  deter- 
mined by  Meek). 

nitida  Meek  &  Worthen,  1873.    Geol.  Stirv.  111.,  vol.  v,  p.  572,  pi.  xxv,  fig.  1. 
For  description  and  synonoiny,  see  Mon.  Brit.  Foss.  Brach.  Davidson,  vol.  ii,  p.  197. 

Well-marked  examples  of  this  species  occur  in  the  Lower  Carbonifer- 
ous limestone  of  Coal  Hill,  in  the  Pancake  Range,  and  also  on  the  west  side 


214  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

of  Mokomoke  Ridge,  White  Pine  Mining  District,  Nevada.  This  horizon 
is  nearly  equivalent  to  that  in  the  Eureka  District,  where  D.  Newberryi  is  so 
abundant. 


Disciua  connata,  n.  sp. 
Plate  vii,  figs.  3,  3  a. 

Shell  subcircular,  a  little  more  expanded  in  front  than  on  the  posterior 
portion. 

The  larger  or  upper  valve  is  depressed  conical  with  the  apex  below  the 
greatest  elevation  of  the  shell  and  near  to  or  on  a  line  with  the  posterior 
margin. 

Surface  marked  by  concentric  striae  and  very  delicate  radiating  lines, 
the  latter  showing  more  prominently  on  the  interior  of  the  shell. 

The  only  interior  markings  shown  are  two  long,  slender,  slightly  ele- 
vated median  ridges  with  a  shallow  depression  between  them. 

Dimensions:  width,  3cm;  elevation  of  upper  valve,  8mm.  There  are  two 
specimens  of  the  upper  valve  of  this  fine  Discina  in  the  collection,  both  of 
which  have  the  apex  nearly  over  the  posterior  margin.  It  may  be  that  it 
is  only  a  variety  of  Discina  nitida,  but  with  our  present  knowledge  of  the 
two  forms  a  specific  name  is  given  to  it. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  the  east  side  of 
Secret-canon-road  Canon,  Eureka  District,  Nevada. 


Genus  PEODUCTUS  Sowerby. 

Productus  Bubaculeatus  March. 
Plate  vii,  fig.  2. 

Synonomy :  See  descriptions  of  Devonian  Brachiopods,  ante,  p.  128. 

A  direct  comparison  with  the  Upper  Devonian  specimens  of  this  species 
shows  that  the  Lower  Carboniferous  specimens  are  identical,  although  a 
belt  of  conglomerate  3,000  feet  in  thickness  separates  them  in  the  geologic 
section. 


FOSSILS  OF  THE  CARBONIFEEOUS. 


15 


The  Carboniferous  form  is  associated  with  Productus  Cora,  P.  semire- 
ticulatus,  P.  muricatus,  P.  elegans,  Spirifera  Eockymontana,  S.  camerata,  etc. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Genus  SPIKIFERA  Sowerby. 

Spirifera  trigonalis  Martin  (Sp.). 
Plate  xviii,  fig.  11. 

Conchyliolites  anomites  trigonalis  Martin,  1809.    Pet.  Derb.,  tab.  xxxvi,  fig.  1. 

Spirifer  trigonalis  Sowerby,  1820.    Min.  Con.,  tab.  265,  fig.  1  (not  2  and  3). 

Spirifera  trigonalis,  var.  a,  McCoy,  1855.     Brit.  Pal.  Foss.,  p.  423. 

trigonalis  Davidson,  1858.    Brit.  Carb.  Brachiopoda,  p.  29,  pi.  v,  figs.  25- 

34;  35-37? 

lisulcata  Davidson,  1861.  Ibid.  Mr.  Davidson  gives  the  synonomy  up  to  the 
date  of  his  publication,  1853,  also  that  of  Spirifera  crassa  De  Koninck,  Spiri- 
fera grandicostata,  and  S.  transiens  McCoy,  which  he  regards  as  forms  of  this 
widely  varying  species. 

Spirifer  increbescens  Hall,  1S5S.    Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  700,  pi.  xxvii,  figs.  6a-i. 

After  a  most  careful  study  of  a  large  series  of  specimens  of  this  species, 
Mr.  Davidson  has  united  all  the  forms  previously  placed  under  the  species 
mentioned  in  the  list  of  synonyms  as  variations  of  a  single  very  variable 
species  and,  in  speaking  of  the  winged,  simple  form  and  the  transversely 
oval,  rounded,  thickened  variety  crassa,  says:  "The  notion  of  both  being 
the  modification  of  a  single  species  will,  to  the  generality  of  observers, 
appear  absurd ;  still  if  we  find  every  variation  connecting  these  extremes, 
are  we  to  refuse  the  evidence  of  our  eyes  and  senses,  and  to  create  as  many 
species  as  we  possess  specimens?"  An  examination  of  Mr.  Davidson's  beauti- 
ful illustrations  cannot  fail  to  convince  one  of  the  specific  relationship  of 
the  different  forms,  and  I  have  no  doubt  that  the  Nevada  shell  before  me  is 
one  of  the  varieties  of  this  widely-distributed  species. 

In  the  Mississippi  Valley  it  is  found  in  the  Chester  limestone  of  the 
Lower  Carboniferous  formation  of  the  State  of  Illinois,  and  described  by 
Professor  Hall  as  Spirifera  increbescens.  Mr.  Davidson  states  that  it  is 
abundant  in  England,  Ireland,  and  Scotland,  and  that  on  the  Continent  it  is 
found  in  Belgium. 


216  PALEONTOLOGY  OF  THE  EUltEKA  DIST1UOT. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
summit  of  Diamond  Peak,  and  in  the  low  hills  at  the  mouth  of  Hayes' 
Canon,  Eureka  District,  Nevada. 


Spirifera  Leidyi  N.  and  P. 
Plate  xviii,  figs.  4,  4  a. 

Spirifera  Leidyi,  Norwood  &  Pratten,  1855.    Jour.  Acacl.  Nat.  Sci.  Philad.,  2d  series, 

vol.  iii,  p.  72,  pi.  ix,  figs.  2  a-c. 

Spirifera  bifurcatus,  Hall,  1857.    Trans.  Albany  Institute,  vol.  iv,  p.  8. 
Spirifera  bifurcata,  Whitfield,  1882.     Bull.  Amur.  Mas.  Nat.  Hist,,  vol.  i,  No.  3,  p.  47, 

pi.  vi,  figs.  13-15.    In  the  remarks  accompanying  the  latter  reference,  Mr. 

Whitfield  considers  S.  bifurcata  as  a  synonym  of  8.  Leidyi. 

The  only  mention  of  the  occurrence  of  this  species  west  of  the  Missis- 
sippi basin  is  found  in  a  list  of  Carboniferous  fossils  from  the  Oqnirrh  Range, 
Utah,  given  in  the  second  volume  of  the  Geological  Exploration  of  the  For- 
tieth Parallel,  page  447. 

There  appears  to  be  little  doubt  of  the  specific  identity  of  the  Nevada 
shell  with  that  from  the  typical  locality  in  the  Chester  limestone  of  Illinois. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
Richmond  Mountain,  and  on  the  low  hills  south  of  the  mouth  of  Hayes' 
Canon,  Eureka  District,  Nevada. 


Spirifera  aniiectans,  u.  sp. 
Plate  xviii,  figs.  7, 7  a. 

Shell  below  the  medium  size,  somewhat  inflated,  length  and  breadth  as 
3  to  4,  respectively ;  anterior  and  lateral  margins  forming  rather  more  than 
a  semicircle  before  uniting  with  the  cardinal  line,  which  is  about  three-fifths 
the  breadth  of  the  shell. 

Ventral  valve  with  a  strongly  defined  mesial  sinus  extending  to  the 
extremity  of  the  rather  prominent,  incurved  beak ;  the  bottom  of  the  sinus 
is  but  slightly  rounded  and  with  a  scarcely  perceptible  elevated  line  along 
the  center;  the  sinus  is  bordered  by  a  rounded  rib,  outside  of  which,  on 
each  side,  there  are  four  ribs,  the  outer  almost  obsolete  on  the  smooth 


FOSSILS  OF  THE  CAEBOMFEEOUS. 


217 


upper  lateral  slopes  of  the  valve ;  area  beneath  the  beak  unknown,  as  it  is 
concealed  by  the  adhering  matrix.  Dorsal  valve  nearly  as  convex  as  the 
ventral ;  beak  small,  incurved,  and  projecting  a  little  over  the  hinge  margin; 
mesial  lobe  elevated,  about  as  broad  as  the  sinus  of  the  opposite  valve  and 
with  a  slight  median  groove;  lateral  ribs,  four  on  each  side. 

Surface  of  valves  marked  by  fine  concentric  lines  of  growth. 

This  species  is  allied  to  S.  Leidyi,  but  differs  in  the  less  number  of  ribs 
on  the  valves,  and  also  in  the  rounded  lateral  angles. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
Richmond  Mountain,  Eureka  District,  Nevada. 

\ 

Spirifera  ueglecta  Ball. 
Plate  xviii,  fig.  10. 

Spirifer  neglectus  Hall,  1858.    Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  643,  pi.  xx,  fig.  5. 

neglectus  Worthen  &  Meek,  1875.     Geol.  Surv.  Illinois,  vol.  vi,  p.  523,  pi.  xxx, 
figs.  Ic,  2 a. 

This  large  and  strongly-marked  species  of  the  Keokuk  limestone  of  the 
Lower  Carboniferous  of  Iowa  and  Illinois,  is  represented  by  single  valves 
and  one  medium-sized  entire  shell.  There  appears  to  be  a  strong  specific 
identity  between  the  Nevada  specimens  and  those  from  the  Mississippi 
Valley. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
Richmond  Mountain,  and  on  the  east  slope  of  a  small  conical  hill  on  the 
east  side  of  Secret-canon-road  Canon,  Eureka  District,  Nevada. 


Spirifera  desiderata,  n.  sp. 
Plate  vii,  fig.  8. 

Dorsal  valve  subsemicircular  in  outline,  extremities  submucronate, 
moderately  convex ;  mesial  fold  not  very  prominent  and  flattened  across 
the  top,  well  defined  at  the  margins,  and  with  a  slightly  depressed  median 
line. 

Surface  marked  by  about  thirty  simple  rounded  plications,  which  are  of 
moderate  strength  and  little  elevated ;  a  few  concentric  lines  are  shown,  but 


218  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

the  exfoliation  of  the  shell  has  destroyed  any  finer  striae  that  may  have 
existed. 

This  is  essentially  a  Devonian  type,  approaching  such  forms  as  Spiri- 
fera Marcyi,  S.  macronata  (Pal.  N.  Y.,  vol.  iv),  in  their  dorsal  valves;  unfor- 
tunately there  are  no  specimens  of  the  ventral  valve  in  the  collections. 

Formation  and  locality.  —  Lower  portion  of  the  Lower  Carboniferous 
limestone  in  canon  directly  south  of  a  small  conical  hill  on  east  side  of 
Secret-canon-road  Canon,  Eureka  District,  Nevada. 

Subgenus  SPIRIFERINA  D'Orbigny. 

Spiriferina  cristata  Schlotheim. 
Plate  xviii,  tigs.  12,  13. 

Terebratulites  cristatm  Schlotheim,  1810.     Beitr.  z.  Naturg.  d.  verst.  in  Akademie  der 

Weisseuschaften  zu  Miinohen,  pi.  i,  fig.  3. 

Spirifera  octoplicatus  Sowerby,  1827.     Miu.  Coil.,  p.  120,  pi.  562,  tables  2,  3,  4. 
Spirifer  octoplicata?  Hall,  1852.    Stansbnry's  Expd.  Great  Salt  Lake,  p.  409,  pi.  iv, 

figs.  4  a,  b.     (Not  S.  octopllcaius  Sowerby.) 

Kentuckensis  Shumard,  1855.    Geol.  Surv.  Missouri,  vol.  i,  pt.  2,  p.  203. 
Kentuckensis  Hall,  1856.    Pacific  Eailroad  Rep.,  vol.  iii,  p.  102,  pi.  ii;  figs.  10, 

11. 
spinosus  Norwood  &  Pratten,  1855.    Jour.  Acad.  Nat.  Sci.  Philad.,  vol.  iii,  p. 

71,  pi.  ix,  figs.  1  a-d. 

spinosus  Hall,  1858.     Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  706,  pi.  xxvii,  figs.  5o-c. 
Spiriferina  octoplicata  Davidson,  1862.     Quart.  Jour.  Geol.  Soc.  London,  vol.  xviii,  p. 

29,  pi.  i,  figs.  12-13- 
Spirifera  Kentuckensis  var.  propatulus  Shuinard,  1866.    Trans.  St.  Louis  Acad.  Sci., 

vol.  ii,  p.  409. 
laminosus  Geinitz,  1866.    Garb,  und  Dyas  in  Nebraska,  p.  45.     (Not  S.  lami- 

nosus  McOoy.) 
Spiriferina  Kentuckensis  Meek,  1872.     U.  S.  Geol.  Surv.  Nebraska,  p.  185,  pi.  vi,  figs. 

3  a-d;  pi.  viii,  figs.  11  a,  b. 
spinosa  f  Derby,  1874.    Bull.  Cornell  University,  vol.  i,  pt.  2,  p.  23,  pi.  vi, 

figs.  8,  13,  14. 

Kentuckensis  White,  1875.     Expl.  and  Suiv.  West  100th  Meridian,  vol.  iv, 
pt.  1,  p.  138,  pi.  x,  figs. 


Characteristic  specimens  of  this  species  occur  in  the  lower  and  central 
portions  of  the  Carboniferous  rocks  of  the  district,  and  in  the  upper  strata 
they  are  associated  with  a  form  that  is  typical  of  S.  spinosa,  of  the  Chester 
limestone  of  .Illinois.  This  same  association  also  occurs  at  Coal  Hill,  in  the 


FOSSILS  OF  THE  CAEBONIFEEOUS. 


219 


Pancake  Range,  where  numerous  examples  occur  that  may  be  referred  to 
either  form,  according-  as  the  spine  bases  are  more  or  less  prominent,  or  the 
shell  contracted  or  extended  laterally.  On  comparing  these  and  specimens 
of  each  variety  from  the  Mississippi  Valley  it  seems  impossible  to  avoid  the 
conclusion  that  they  are  one  and  the  same  species. 

Fig  12,  plate  xviii,  is  taken  from  a  Chester  limestone  specimen,  and 
the  adjoining  fig.  13  from  a  specimen  found  in  the  Upper  Carboniferous 
limestone  of  the  Eureka  District.  Comparing  these  and  also  the  specimens 
with  Mr.  Davidson's  figures  of  Spiriferina  cristata  Schloth.,  1816r=£  octo- 
plicatus  Sowerby,  1827,  it  appears  that  we  have  another  very  variable  spe- 
cies that  has  a  great  vertical  range  and  an  extended  geographic  distribu- 
tion. Dr.  White  (Expl.  and  Surv.  West  100th  Merid.,  vol.  iv,  pt.  1,  p.  140, 
187 ."•»)  regards  Spiriferina  Kentuckensis  and  S.  octoplicata  as  distinct  species, 
but  with  the  evidence  now  accessible  I  should  be  inclined  to  consider  them 
and  also  £  spinosa  as  varieties  of  one  and  the  same  species 

In  the  Devonian  White  Pine  shale  of  the  White  Pine  Mining  District 
there  is  a  form  that  in  its  plications  is  similar  to  S.  cristata,  and  in  surface 
markings  it  is  very  much  like  S.  insculpta  Phillips.  It  occurs  at  the  summit 
of  the  Devonian,  and  is  referred  to  S.  cristata  Mr.  Davidson  has  recognized 
the  species  in  both  the  Middle  and  Lower  Devonian  (British  Devonian 
Brachiopoda,  p.  123). 

Formation  and  localities. — In  the  Lower  Carboniferous  on  the  east  slope 
of  a  small  conical  hill  on  the  east  side  of  Secret-canon-road  Canon  and  in 
the  Upper  Carboniferous  limestone  of  the  western  slope  and  foothills  of 
Diamond  Peak,  Eureka  District,  Nevada. 


Genus  SYRINGOTHYRIS  Winchell. 
Syringothyris  cuspidata  Martin  (Sp.). 

Anomites  cuspidatus  Martin,  1796.     See  Davidson's  Mon.  Brit.  Carb.Brach.,  p.  44,  and 

supplement,  vol.  iv,  p.  278,  1880. 
Spirifer  cuspidatus  f  Meek,  1877.    Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  87,  pi.  iii,  figs. 

11, 11  a. 

Mr.  Meek  cites  this  species  from  above  the  Devonian  of  the  White  Pine 
Mountains,  Nevada.     It  is  quite  abundant  on  Richmond  Mountain  in  one 


220  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

stratum,  in  association  with  Spirifera  negleda  and  other  Lower  Carboniferous 
fossils,  Eureka  District,  Nevada. 

Specimens  of  S.  cuspidatus  have  recently  been  received  (1884)  from 
the  Lower  Carboniferous  limestone  in  the  Little  Belt  range  of  mountains 
near  Clendenin,  Montana. 

Genus  RETZIA  King. 

Retzia  radialis  Phillips  (Sp.). 

Plate  vii,  figs.  5,  5a-h. 

Terebratula  radialis  Phillips,  1836.    Geol.  Yorkshire,  vol.  ii,  p.  223,  pi.  xii,  figs.  4.0,  41. 
manticee  De  Koirinck,  1843.    Anm.  Foss.,  p.  287,  pi.  xix,  figs.  4o-d.     (Not 

T.  manticB  of  Sowerby.) 

Atrypa  radialis  McCoy,  1844.     Syn.  Garb.  Foss.  Ireland,  p.  156. 
Terebratula  radialis  De  V.  &  De  K.,  1845.    Russia  and  the  Ural  Mountains,  vol.  ii,  p. 

89,  pi.  x,  figs.  9«,  b. 

Retzia  radialis  Morris,  1854.     Cat.  Brit.  Foss.,  p.  145. 
Spirigerina  ?  radialis  McCoy,  1855.    Brit.  Pal.  Foss.,  p.  438. 
Terebratula  Mormoni  Marcou.     Geol.  North  America,  p.  51,  pi.  vi,  figs,  llo-c. 
Retzia  punctilifera  Shutnard,  1858.     Trans.  St.  Louis  Acad.  Sci.,  vol.  i,  p.  220. 

Mormoni  Meek  &  Hayden,  1859.     Proc.  Acad.  Nat.  Sci.  Philad.,  vol.  xi,  p.  27 ; 

Geinitz,  1864.    Carb.  und  Dyas  in  Neb.,  p.  39,  tab.  iii,  fig.  6. 
snbglobosa  McChesney,  1860.     Descriptions  New  Pal.  Fossils,  p.  45,  and  pi.  i, 

fig.  1.     Illustrations  of  same,  1865. 
radialis  Davidson,  1861.    Mon.  Brit.  Carb.  Brachiopoda,  pp.  87,  218,  pi.'  xvii, 

figs.  19-21;  pi.  Ii,  figs.  4-9. 
radialis  Phillips,  (sp.),  var.  yrandicosta  Davidson,  1861.     Carb.  Brach.  Coll.  in 

India,  Quart.  Jour.  Geol.  Soc.,  vol.  xviii,  p.  28,  pi.  i,  fig.  5. 
compressa  Meek,  1864.      Geol.  Surv.  California,  Pal.,  vol.  i,  p.  14,  figs.  7  a-c. 

Kayser,  1882.     Riehtbofen,  China,  vol.  iv,  p.  176,  tab.  xxii,  figs.  1-4. 
punctulifera  McChesney,  1867.     Trans.  Chicago  Acad.  Sci.,  vol.  i,  p.  32,  pi.  i, 

fig.  1. 
punctulifera  Meek,  1872.     U.  S.  Geol.  Surv.  Nebraska,  p.  181,  pi.  i,  fig.  13,  pi. 

v,  tig.  8. 
Mormoni  White,  1875.     Expl.  and   Surv.  West  ^OOth  Merid.,  vol.  iv,  pt.  1,  p. 

141,  pi.  x,  figs.  7  a-c. 

Compare  Retzia  Marcyi  Shumard,  1854,  Expl.  Red  River  of  Louisiana,  p.  190,  pt.  l,fig. 
4a,  b;  also,  Retzia  VerncnUlana  and  R.  vera  Hall,  Geol.  Surv.  Iowa,  vol. 
i,  pt.  2,  pp.  657,  704,  1858. 

On  bringing  together  a  series  of  specimens  of  this  species  from  Ne- 
vada and  New  Mexico  it  became  at  once  apparent  that  it  was  very 


FOSSILS  OF  THE  CABBONIFEKOUS. 


221 


variable,  and  also  specifically  identical  with  the  widely  distributed  E.  radi- 
alis.  All  the  specimens  agree  in  general  form,  the  presence  of  a^small 
area  and  a  vertically  ribbed,  punctate  shell.  In  the  number  and  strength 
of  the  radiating  costse,  however,  the  greatest  difference  is  shown.  I  now 
have  before  me  specimens  with  7,  10,  12,  13,  17,  22,  and  2">  costse  on  each 
valve.  With  the  two  extremes  to  base  a  separation  on  both  Eetzia  Mormoni 
Marcou,  and  E.  radialis,  var.  grandicosta  Davidson,  appear  as  good  species — 
one  characterized  by  a  few  angular  radiating  ribs,  and  the  other  by  numer- 
ous rounded  radiating  ribs.  With  the  intermediate  links  to  connect  the 
shell  with  seven  ribs  and  that  of  twenty-five  and,  also,  any  variations  of 
form  that  occur  among  many  examples,  we  are  necessitated  to  unite  all 
under  one  species,,  and  to  refer  it  to  Eetzia  radialis  of  Phillips,  as  Davidson 
has  shown  that  that  species  has  the  same  range  of  variation  in  the  number 
and  character  of  the  radiating  ribs,  and  a  comparison  of  the  American 
specimens  with  his  figures  and  descriptions  leaves  little,  if  any,  doubt  of 
the  specific  identity  of  the  two. 

In  the  White  Pine  shales  of  the  Upper  Devonian  of  the  White  Pine 
Mining  District,  Nevada,  a  shell  occurs  that  is  identical  with  the  more  finely- 
ribbed  examples  from  the  Lower  Carboniferous  limestone  of  the  Pancake 
Mountains  (situated  between  White  Pine  and  Eureka)  and  those  occurring 
at  relatively  the  same  horizon  near  Santa  Fe*,  New  Mexico. 

As  far  as  our  observations  go,  the  finely-ribbed  variety  appears  first  in 
the  Upper  Devonian,  and  the  more  coarsely  ribbed  in  the  Middle  Carbon- 
iferous in  association  with  the  intermediate  forms,  uniting  them  with  the 
finely-ribbed  variety. 

The  coarsely-ribbed  variety  described  by  Davidson,  from  the  Punjab, 
India,  is  represented  by  the  Nevada  shell  bearing  seven  plications,  and  the 
more  finely-ribbed  form  from  Russia  is  the  usual  variety  from  England, 
Belgium,  and  America. 

Dr.  Kayser  has  placed  the  specimens  representing  the  species  in  China 
under  E.  compressa  Meek;  a  variety  of  E.  radialis  Phillips.  All  the  differ- 
ences mentioned  by  Meek  as  characterizing  E.  compressa,  as  distinct  from 
E.  punctulifera,  are  shown  in  a  good  series  of  E.  radialis. 


222  PALEONTOLOGY  OF  THE  EUEEKA  DJSTEICT. 

Retzia  Marcyi  Shumard  is  probably  a  finely-ribbed  variety  of  R.  radialis, 
and  a  large  series  of  specimens  may  bring  R.  vera  and  R.  Verneuiliana  of 
the  Lower  Carboniferous  limestone  of  Iowa  into  the  same  group  as  varieties. 

As  now  known  in  Central  Nevada,  R.  radialis  ranges  from  the  Upper 
Devonian  through  the  Lower  into  the  Upper  Carboniferous  limestone,  a 
horizon  equivalent  to  that  of  the  Upper  Coal  Measures,  where  it  is  found 
in  Nebraska,  Illinois,  etc.  Its  great  geographic  range  has  already  been 
noticed  in  speaking  of  its  occurrence  in  China,  India,  the  Ural  Mountains, 
England,  and  Western  America. 


Genus  ATHYEIS  McCoy. 

Athyris  hirsuta  Hall. 
Plate  xviii,  fig.  5. 

Spirigera  (Athyris)  hirsuta  Hall  1857.15    Trans.  Albany  Institute,  vol.  iv,  p.  8. 
Athyris  sublamellosa  Hall,  1858.    Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  702,  pi.  xxvii,  fig. 

1  a-c.    Idem.,  Derby,  1874.    Bull.  Cornell  University,  vol.  i,  No.  2,  p.  10, 

pi.  ii,  figs.  9-12;  pi.  iii,  figs.  15,  21,  29;  pi.  vi,  fig.  16;  pi.  ix,  figs.  5,  6. 
Athyris  hirsuta  Whitfield,  1882.    Bull.  Ainer.  Mus.  Nat.  Hist.,  vol.  i,  p.  49,  pi.  vi,  figs. 

18-21. 

Compare  Athyris  Royssii.     See  Brit.  Foss.  Brach.  Davidson,  vol.  ii,  p.  84. 

There  is  so  little  difference  between  the  examples  of  this  species  from 
Nevada  and  those  from  the  Chester  limestone  of  Illinois,  that  the  lithologic 
features  of  the  matrix  alone  distinguishes  them.  It  is  not  improbable 
tiiat  this  species  is  founded  on  a  small  variety  of  Athyris  Royssii,  and  Mr. 
Meek  has  placed  it  as  a  doubtful  synonym  (Geol.  Expl.  Fortieth  Par.,  vol. 
iv,  p.  82). 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
Diamond  Peak,  in  the  Eureka  District,  and  at  Coal  Hill,  Pancake  Range, 
Nevada. 

16  The  paper  describing  the  Spergen  Hill  fossils  \vas  printed  aud  copies  distributed  in  1857  in 
advance  of  the  publication  of  Volume  IV  of  the  Albany  Institute  Transactions,  which  bears  date 

1858-1864. 


FOSSILS  OF  THE  CAEBON1FEROUS. 


Genus  RHYNCHONELLA  Fischer. 


223 


Rhynchonella  Eurekensis,  n.Jsp. 
Plate  xviii,  figs.  8,  8a-c. 

Shell  below  the  average  size;  somewhat  trigonal  in  outline;  the  width 
and  height  subequal,  or  the  latter  a  little  greater  than  the  former;  dorsal 
valve  a  trifle  deeper  than  the  ventral. 

Ventral  valve  with  a  prominent  beak  and  strongly  marked  but  not 
deep  mesial  sinus  that  is  about  one-half  the  width  of  the  shell  at  the  front 
margin ;  sides  sloping  gradually  away  from  the  edges  of  the  sinus  and  more 
abruptly  from  the  somewhat  elevated  upper  portion.  Dorsal  valve  much 
more  convex  than  the  ventral  and  marked  by  a  slight,  broad  mesial  fold  on 
the  lower  portion;*  beak  strongly  incurved;  general  surface  rounding  to  the 
margins  from  the  central  portions  of  the  valve. 

Surface  of  the  valves  marked  by  from  40  to  50  round,  simple  plications. 

This  species  is  distinguished  from  any  described  by  its  general  form 
and  the  numerous  radiating  plications. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon-road 
Canon,  and  on  the  northeast  side  of  the  canon  north  of  Pinto  Peak,  Eureka 
District,  Nevada. 

Rhynchonella  Thera,  n.  sp. 
Plate  vti,  figs.  6,  6o-c. 

Shell  small,  subglobose  or  suboval,  strongly  convex,  with  a  prominent 
mesial  elevation  and  suture. 

Ventral  valve  a  little  less  convex  than  the  dorsal,  the  greatest  con- 
vexity being  on  the  posterior  half;  below  the  middle  a  broad,  not  very 
sharply  defined  sinus  begins,  which  becomes  deeper  and  expands  towards 
the  front;  beak  imperforate  and  slightly  curved  over  that  of  the  opposite 
valve. 

Dorsal  valve  most  convex  at  the  middle;  the  median  fold  is  not  usu- 
ally strongly  defined ;  it  has  a  slight  central  sinus  that  reaches  from  near 
the  beak  out  to  the  front  termination  of  the  fold,  the  latter  starting  about 
the  center  of  the  shell.  Surface  marked  by  fine  concentric  lines  of  growth. 


224  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

This  species  is  related  by  its  form  to  Athyris  f  polita  Hall  (Pal.  N.  Y , 
vol.  iv,  p.  293),  of  the  Chemung  Group  of  New  York,  and  also  in  some  of 
the  specimens  to  Athyris  trinudea  (see  Bull.  Amer.  Mus.  Nat.  Hist.,  vol.  i,  p. 
50),  of  the  Lower  Carboniferous  of  Indiana,  etc.;  the  beak  of  the  ventral 
valve,  however,  appears  to  be  imperforate. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  Conical  Hill,  on  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


Genus  CAMAROPHORIA  King. 

Camarophoria  Cooperensis  Shumard  f 

Plate  xviii,  fig.  6. 
Rhynchonella  Cooperensia  Shuinai  cl,  1855.    Geol.  Surv.  Missouri,  pt.  2,  p.  204,  pi.  (7, 4o-<7. 

With  the  exception  of  having  fewer  plications,  the  Eureka  specimens 
agree  in  all  essential  features  with  those  from  the  Chouteau  limestone  of 
Missouri,  as  described  by  Dr.  Shumard.  A  comparison  of  specimens  may 
show  the  western  form  to  be  a  distinct  species,  but  the  means  of  comparison 
at  present  available  leads  to  referring  them  as  above. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
on  the  western  slope  of  Richmond  Mountain,  and  in  limestone  capping 
Diamond  Peak,  Eureka  District,  Nevada. 

Genus  TEREBRATULA  Llhwyd. 

Terebratula  hastata  Sowerby. 
Synonymy:  See  Mou.  Brit.  Foss.  Braeb.  Davidson,  vol.  ii,  p.  11. 

With  a  number  of  specimens  to  compare  with  Mr.  Davidson's  beauti- 
ful figures  of  this  species  we  cannot  find  reasons  for  a  specific  separation  of 
the  American  form  from  that  of  Europe.  Some  of  the  Eureka  shells  are  a 
little  more  expanded  in  front,  but  scarcely  more  so  than  examples  figured 
by  Mr.  Davidson. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill,  on  east  side  of  Secret- 
cafion-road  Canon,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CARBONIFEEOUS. 


225 


LAMELLIBRANCHIATA. 

The  occurrence  of  a  number  of  species  of  this  class  in  the  Carbonifer- 
ous Group,  in  the  region  of  the  Rocky  Mountains,  is  unusual,  as  heretofore 
it  has  been  but  sparingly  represented. 

In  1852  Prof.  J.  Hall  (Stansbury's  Expedition  to  the  Great  Salt  Lake, 
p.  412)  described  a  few  species,  viz:  Avicula^Pseudomonotis  curta,  Tellino- 
mya  protensa  (probably  belongs  to  the  genus  Modiomorpha),  Allorisma 
terminalis,  Cypricardia  occidentalis,  Nucula  arata. 

Of  these  the  last  three  species  were  obtained  from  Eastern  Nebraska  or 
the  Mississippi  Valley  region.  To  the  first  two  may  be  added  twenty-two 
species  mentioned  by  different  authors: 

Marcou,  J.,  1858.    Geology  of  North  America,  p.  44.    Myalina  Apachesi. 

Meek,  F.  B.,  1860.  Preliminary  Notice.  1876.  Report  Explorations  Across  the  Great 
Basin  of  Utah,  Simpson,  p.  354.  Aviculopecten  UtaJiensis. 

White,  C.  A.,  1874.  Preliminary  Notice.  1875.  Explorations  and  Surveys  West  of 
the  100th  Meridian,  vol.  iv,  pt.  1,  p.  146.  Aviculopecten  occidentalis,  A.  Corey- 
anus,  A.  McCoyi,  A.  f  interlineatus,  Pinna  peracuta? ,  Monopteria  Marian,  My- 
alina, sp.,  M.  f  Sicallovi,  Balcevellia  parva,  Schizodus  Wheeleri,  Allorisma 
subcuneata,  var.  Also,  in  Appendix  to  Supplement  of  vol.  iii  of  the  same 
Survey,  1881,  p.  xxv.  Myalina  Permiana  and  Pleurophorus  subcostatus. 

Whitfield,  R.  P.,  1875.  Carroll,  Montana,  to  Yellowstone  National  Park,  Ludlow,  p. 
143.  Pinna  Ludlovi. 

Meek,  F.  B.,  1877.  Geological  Exploration  of  the  Fortieth  Parallel,  vol.  iv,  p.  96.  A. 
occidaneus. 

Two  other  species  are  described  as  from  the  Carboniferous,  but  they 
are  more  properly  referred  to  the  Devonian  by  Messrs.  Hall  and  Whitfield. 

Hall,  J.,  and  Whitfield,  R.  P.,  1877.  Geological  Exploration  of  the  Fortieth  Parallel,  vol. 
iv,  p.  273.  Aviculopecten  Webcrensis,  A.  curto-cardinalis,  A.  parvulus,  Mya- 
lina  aviculoides,  M.  Permiana,  SedgwicTcia  f  concava,  Cardiomorpha  Missou- 
riensis. 

The  latter  species,  Cardiomorpha  Missouriensis,  although  described  from 
the  Coal  Measures  of  Missouri  and  Illinois,  is,  in  Nevada,  found  in  the  strata 
at  the  summit  of  the  Devonian  and  is  not,  there,  a  Carboniferous  species; 
with  this  exception,  all  of  the  twenty-four  species  heretofore  described  are 
from  the  upper  portions  of  the  Carboniferous  Group,  usually  referred  by 
authors  to  the  Coal  Measures.  From  the  latter  horizon  but  one  species  is 
15  o  D  w 


226  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

added,  Macrodon  tenuistriata ;  all  the  others  from  the  Eureka  District  occur 
in  the  lower  portion  of  the  Lower  Carboniferous  limestone.  The  relations 
of  the  greater  number  of  the  species  are  with  Devonian  and  Lower  Carbon- 
iferous species  rather  than  with  those  of  the  Coal  Measure  Groups  of  the 
Mississippi  Valley. 

Two  species,  Macrodon  Hamiltonce  and  Grammysia  arcuata,  belong  to  the 
Middle  Devonian  in  New  York,  and  Grammysia  Hannibaknsis  and  Sangui- 
nolites  JEolus  occur  in  the  Chemung  and  Waverly  Groups. 

Larger  collections  from  the  localities  already  known  in  the  Eureka 
District  will  undoubtedly  add  materially  to  the  number  of  species,  if  not 
genera,  already  described,  as  many  fragments  of  unidentified  forms  occur 
in  the  collection;  but  with  twenty-one  genera,  represented  by  forty-five 
species,  to  add  to  those  already  mentioned  by  the  above  authors,  the  Lamelli- 
branchiata  is  fairly  represented  in  the  Carboniferous  system  of  Nevada. 


Genus  AVICULOPECTEN  McCoy. 

Aviculopecten  Haguei,  n.  sp. 
Plate  xix,  fig.  4. 

Shell  large,  oval  or  suborbicular  in  outline,  exclusive  of  the  ears;  left 
valve  depressed  convex,  hinge-line  about  three-fourths  of  the  greatest 
width  below;  umbonal  margins  converging  to  the  beak  at  an  angle  of  90°; 
lateral  margins  rounding  into  the  regularly  curved  pallial  margin;  pos- 
terior ear  larger  than  the  anterior,  less  obtuse,  and  not  so  distinctly  defined 
by  the  angle  of  the  umbonal  slope;  the  sinuses  separating  the  ears  from  the 
lateral  margins  are  shallow,  the  posterior  being  more  broadly  rounded  than 
the  anterior. 

Surface  of  each  ear  ornamented  by  fine  concentric  striae,  and  that  of 
the  posterior  by  5  or  6  narrow,  radiating  costae;  in  addition,  the  body  of 
of  the  valve  is  marked  by  numerous  rounded  radiating  costae,  that,  towards 
the  pallial  margin,  become  subangular,  with  a  quite  broad  interspace  between 
them ;  the  concentric  striae  that  are  so  marked  on  the  ears  are  scarcely  dis- 
cernible except  on  the  outer  portions  of  the  shell,  owing  to  the  imperfect 
state  of  preservation  of  the  outer  surface. 


FOSSILS  OF  THE  CARBONIFEROUS. 


227 


Dimensions :  height,  9.5cm;  width,  8cm;  convexity  of  left  valve,  1.25cm. 

This  is  an  unusually  large  and  strongly  marked  species,  and  unlike  any 
described  from  this  horizon. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
east  side  of  Secret-canon-road  Cafion,  on  the  east  slope  of  a  small  conical 
hill,  Eureka  District,  Nevada. 


Aviculopecten  Eurekensis,  n.  sp. 
Plate  xix,  figs.  2, 3. 

General  outline  exclusive  of  the  ears  subovate,  varying  somewhat  in 
different  specimens.  General  surface  moderately  convex  when  not  acci- 
dentally compressed;  ears  subequal  in  size,  the  posterior  being  the  larger,  the 
anterior  shorter  and  more  obtuse.  Hinge-line  less  than  the  greatest  width 
of  the  shell.  Beak  small,  obtusely  pointed. 

Surface  marked  by  from  18  to  25  simple  lines  or  radiating  costse,  that 
are  crossed  by  fine  concentric  striae.  Left  valve  unknown.  The  hinge  is 
smooth  each  side  of  the  beak. 

Dimensions :  height  of  narrow  form,  4cm;  of  broad  form,  3.5cm;  width, 
3.5cm  and  4cm;  convexity  of  left  valves,  lcm  and  0.75cm,  respectively. 

This  species  is  allied  to  A.  Haguei,  but  differs  in  having  about  one-half 
the  number  of  radiating  surface  costre. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-cafion-road 
Canon,  Eureka  District,  Nevada. 


Aviculopecten  peroccidens,  n.  sp. 

Plate  viii,  fig.  8. 

General  outline,  exclusive  of  the  ears,  suborbicular  to  subovate  in  the 
more  elongate  specimens.  General  surface  rather  strongly  convex  when 
not  flattened  by  accidental  compression.  Anterior  ear  considerably  smaller 
than  the  posterior.  Hinge-line  less  than  the  greatest  width  of  the  shell 
below.  Beak  subcentral.  Angle  of  divergence  of  the  body  of  the  shell 
from  the  beak,  within  the  ears,  110°. 


228  PALEONTOLOGY  OF  THE  EUEEKA  DISTJRIOT. 

Surface  marked  by  from  25  to  30  simple  radiating  costae,  the  inter- 
spaces wider  than  the  costse,  and  with  intercalated  smaller  costse  rising  in 
some  of  them;  concentric  striae  and  lines  of  growth  are  more  or  less  dis- 
tinctly shown.  Right  valve  unknown. 

The  interior  of  the  hinge  unknown. 

Dimensions:  height  and  width  of  average  size  specimen,  3.5cm;  con- 
vexity of  left  valve,  .75cm. 

This  species  shows  considerable  similarity  to  A.  Eurekensis.  It  differs 
in  the  presence  of  a  larger  number  of  costse  and  in  its  more  orbicular  form. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  'a  conical  hill  on  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 

Aviculopecten  Piiitoensis,  n.  sp. 
Plate  viii,  fig.  6. 

Shell  small,  rounded  ovate  in  outline  exclusive  of  the  wings\  Left 
valve  gently  convex.  Hinge-line  about  two-thirds  as  long  as  the  greatest 
width  of  the  shell  below.  Ears  subequal  in  size,  the  anterior  with  a  some- 
what more  deeply  cut,  rounded  sinus  beneath.  Beak  small,  obtusely 
pointed  and  scarcely  extending  beyond  the  cardinal  margin. 

Surface  marked  by  numerous  fine  radiating  linear  costae,  twenty  in 
a  distance  of  five  millimeters,  with  a  few  finer  striae  or  costae  in  some  of  the 
interspaces;  the  costae  are  present  on  the  ears  and  are  strongly  defined  on 
the  anterior  ear;  a  few  concentric  lines  of  growth  appear  on  the  posterior 
ear  and  extend  on  to  the  disk  of  the  shell  as  rather  indefinite  undulations 
or  lines  of  growth. 

Interior  characters  unknown. 

Dimensions:  height,  2cm;  width,  2cm;  convexity  of  left  valve,  2mm. 

This  pretty  little  shell  is  of  the  type  of  Aviculopecten  Coxanus  M.  and 
W.  (Geol.  Surv.  111.,  vol.  ii,  plate  xxvi,  fig.  6  «,  &),  differing  only  in  its  more 
erect  form  and  shorter  ears.  In  form"  it  also  approaches  A.  (Pecteii)  plicatus 
Sowerby,  as  figured  by  De  Koninck  (Anm.  Foss.,  plate  iv,  fig.  6). 

Formation  and  locality. — Lower  portion  of  Carboniferous  Group,  in 
canon  north  of  Pinto  Peak,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CARBONIFEROUS. 


229 


Aviculopecten  affinis,  n.  sp. 
Plate  xix,  figs.  1,  1  a. 

Shell  of  medium  size.  Left  valve,  exclusive  of  the  ears,  suborbicular 
in  outline,  depressed  convex;  hinge-line  varying  from  two-thirds  to  five- 
sixths  of  the  greatest  width  below;  posterior  margin  most  prominent  at  the 
transverse  center  of  the  shell  from  where  it  curves  gently  and  nearly  per- 
pendicularly downward  to  the  somewhat  abruptly  rounded  basal  margin, 
and  upward  to  the  sinus  beneath  the  ear;  anterior  margin  most  prominent 
above  the  center,  from  which  it  curves  nearly  as  the  opposite  margin  to  the 
base,  and  above,  more  abruptly;  ears  subequal,  subtriangular  in  form,  and 
defined  by  a  sinus  that  varies  in  depth  and  shape  on  different  shells;  beak 
subcentral,  pointed,  and  extending  above  the  hinge-line. 

Surface  of  both  ears  and  the  body  of  the  valve  ornamented  with  num- 
erous fine  radiating  costae,  every  third  or  fourth  one  of  which  is  raised 
above  the  intervening  costaer  the  latter  usually  running  out  before  reaching 
the  umbo;  fine  concentric  striae  cross  the  radiating  striae  on  the  ears  and 
body  of  the  valve,  being  more  strongly  marked  on  the  anterior  ear. 

Eight  valve  nearly  flat,  with  a  stronger  sinus  under  the  anterior  ear,  and 
the  surface  marked  by  numerous  simple  radiating  striae  and  concentric  striae 
on  the  ears. 

An  examination  of  many  specimens  in  all  conditions  of  preservation 
fails  to  show  any  crenulations  on  the  hinge  margin,  although  the  interior  is 
well  preserved  in  several  examples. 

This  species  varies  considerably  in  the  outline  of  the  valves;  some  are 
longer  than  wide  and  others  with  length  and  width  subequal  In  the  latter 
case  the  left  valve  is  somewhat  like  that  of  Crenipecten  Winchetti  Meek,  of 
the  Waverly  Group  of  Ohio.  (See  Pal.  N.  Y.,  vol.  v,  pt.  1 ,  plate  ix,  figs. 
1,  2,  4,  25-30.)  The  right  valve,  however,  is  finely  but  strongly  striate 
longitudinally,  while  that  of  C.  Winchetti  is  nearly  smooth,  except  on  the 
ears. 

This  is  a  very  abundant  species  in  two  localities,  almost  filling  some 
of  the  layers  on  the  little  conical  hill  on  the  east  side  of  Secret-canon-road 
Canon,  where  it  is  associated  with  A.  Haguei,  A.peroccidens,  and  A.  EureJcensis. 


230  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group 
with  the  preceding,  and  also  on  the  west  slope  of  Richmond  Mountain, 
Eureka  District,  Nevada. 

Aviculopecten,  8p.  f 

Two  other  species  of  the  genus  are  shown  by  rather  large-sized  shells, 
but  their  condition  is  such  that  the  specific  determination  would  be  uncer- 
tain, and  with  the  genus  so  well  represented  they  are  left  for  more  material 
and  future  study  to  determine  their  specific  relations. 

Genus  STREBLOPTERIA  McCoy. 

Streblopteria  siniilis,  n.  s]>. 
Plate  viii,  figs.  4,  4a-d,  and  plate  xis,  fig.  7 

Shell  of  medium  size;  outline,  exclusive  of  the  anterior  ear,  ovate, 
general  surface  depressed  convex.  The  two  valves  are  very  much  alike  in 
convexity  and  form,  except  at  the  anterior  ear  and  the  slope  beneath;  the 
right  valve  has  a  deep,  sharply-cut  byssal  sinus  beneath  the  ear,  the  ear 
joining  the  body  of  the  shell  higher  up  towards  the  beak.  The  posterior 
ear  is  either  very  short  and  small,  or  obsolete,  being  merged  into  the  flat- 
tened posterior  umbonal  slope.  Hinge-line  very  short.  Beaks  small,  the 
sides  sloping  away  at  an  angle  of  about  80°. 

Surface  of  the  larger  shells  smooth  or  with  fine  concentric  striae  and 
lines  of  growth;  a  few  very  indistinct  fine  radii  are  present  towards  the  lower 
margin;  the  anterior  ear  of  the  right  valve  is  marked  by  concentric  lines 
of  growth  and  rather  strong  radiating  costse;  on  the  left  valve  the  anterior 
ear  has  only  the  concentric  strise.  On  all  the  smaller  shells  the  raised  ra- 
diating striae  or  fine  costse  are  present  in  varying  degrees  of  distinctness  up 
to  well-marked  striated  forms  that  in  surface  characters  apparently  have  no 
specific  relation  to  the  large,  smooth  shells 

Dimensions:  height  of  two  examples,  3.75cm  and  1.75cm;  breadth,  3.25om 
and  1.5cm;  convexity  of  larger,  4mm;  of  smaller,  about  2mm. 

The  peculiar  obliquity  of  the  valves,  the  deeply-cut  sinus  beneath  the 
anterior  ear  of  the  right  valve,  and  the  smooth  surface  relates  this  species 


FOSSILS  OF  THE  CARBONIFEKOUS. 


231 


to  Streblopteria  Icevigata  McCoy  (Brit.  Pal.  Foss.,  p.  482),  the  type  of  the 
genus.  The  form  is  also  that  of  species  referred  to  the  genus  Pernopecten, 
but  in  a  large  number  of  examples  I  have  not  been  able  to  find  the  crenu- 
lated  hinge  area  characteristic  of  that  genus;  the  species  agrees  more  closely 
with  Streblopteria  in  other  characters.  The  smaller  shells  resemble  Pecten  ? 
pusillus  of  the  Permian  (see  Mon.  Perm.  Foss.,  England,  p.  153),  but  differ 
in  having  a  longitudinally  striated  surface. 

Streblopteria  tenuilineatus  M.  and  W.  (Geol.  Surv.  Ill,  vol.  ii,  plate  xxvi, 
fig.  9  a)  is  the  only  American  species  that  has  been  referred  to  the  genus. 
It  differs  very  materially  in  form  and  surface  characters  from  the  species 
under  consideration. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group  in 
the  canon  north  of  Pinto  Peak;  on  the  west  slope  of  Richmond  Mountain, 
and  in  the  canon  south  of  a  small  conical  hill  on  the  east  side  of  Secret- 
caflon-road  Canon,  Eureka  District,  Nevada. 


Genus  CRENIPECTEN  Hall. 

The  genus  Crenipecten  is  described  by  its  author  as  "Like  Aviculopec- 
ten  in  form,  hinge  furnished  with  a  series  of  small  cartilage  pits  throughout 
its  entire  length."  Example,  Crenipecten  Leon  and  C.  crenulatus  (Pal.  N.  Y., 
vol.  v,  pt.  1,  1884). 

The  study  of  the  species  referred  to  Aviculopecten  from  the  Eureka 
District  shows  but  one  species  that  has  such  a  hinge.  A.  affinis,  A.  Eure- 
kensis,  A.  peroccidens,  A.  Haguei  have  a  flattened  hinge,  but  in  none  of  the 
examples  of  those  species  have  we  detected  any  vertical  ligamental  pits  as  in 
Crenipecten. 

,  Crenipecten  Hallanus,  n.  np. 

Plate  viii,  figs.  7,7a-c. 

Shell  rather  above  medium  size;  outline,  exclusive  of  the  ears,  sub- 
orbicular.  General  surface  moderately  convex.  Hinge-line  and  greatest 
width  of  the  shell  as  4  to  5  ;  5  to  6  in  two  examples.  Anterior  ear  smaller 


232  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

than  the  posterior,  and  also  with  an  abruptly  curved  sinus  beneath  it.  Beaks 
small  and  abruptly  pointed,  subcentral  in  position  on  the  hinge-line. 

Surface  of  both  right  and  left  valves  marked  by  linear,  radiating,  raised 
striae  that  increase  in  number  towards  the  margin  by  the  striae  originating 
in  the  gradually  widening  interspaces  between  the  initial  striae,  the  striae  at 
the  basal  margin  being  about  lmm  apart.  Fine  concentric  striae  cross  the 
radiating  elevated  striae  or  costae. 

The  left  valve  of  this  species  is  closely  allied  to  that  of  Crenipectm 
Winchelli  (see  Pal.  N.  Y.,  vol.  v.,  pt.  1,  p.  89),  except  in  being  more  robust. 
In  the  right  valve  marked  differences  occur  in  the  surface  characters  and 
the  shape  of  the  anterior  ear.  With  Aviculopecten  affinis  it  is  more  closely 
related,  differing  mainly  in  the  form  and  proportion  of  the  ears,  in  its  more 
robust  form,  and  the  presence  of  the  liganiental  pits  on  the  hinge-line, 
which,  as  yet,  have  not  been  observed  in  the  latter,  although  the  conditions 
for  their  preservation  and  discovery  appear  to  be  much  better  than  in  C. 
Hallanus. 

Formation  and  localities. — Lower  portion  of  the  Lower  Carboniferous 
Group  in  the  cafion  north  of  Pinto  Peak,  and  also  on  the  east  slope  of  a 
small  conical  hill  on  the  east  side  of  Secret-canon-road  Cafion,  Eureka 
District,  Nevada. 

N 

Genus  PTERINOPECTEN  Hall. 

Pterinopecten  Hoosacensis,  n.  sp. 

Plate  viii,  fig.  9. 

Outline  truncato-ovate.  Left  valve  depressed  convex.  Hinge-line 
nearly  as  long  as  the  greatest  width  of  the  shell  below.  Anterior  ear  de- 
fined by  a  strong  rounded  sinus;  posterior  ear  scarcely  more  than  a  slight 
extension  of  the  postero-lateral  portion  of  the  shell.  Beak  small,  abruptly 
pointed,  and  situated  a  little  anterior  to  the  center  of  the  hinge-line. 

Surface  marked  by  a  few  concentric  lines  of  growth  and  fine,  linear, 
raised  striae  that  increase  in  number  by  intercalation  as  the  initial  striae 
spread  apart,  the  intercalated  striae  appearing  between  them. 

Dimensions:  height,  4.5cm;  breadth,  4.75cm. 


FOSSILS  OF  THE  CABBONIFEKOUS. 


233 


In  outline  this  species* is  not  dissimilar  from  Pterinopecten  (Pecten) 
papyraceus,  as  illustrated  by  De  Koninck  (Anm.  Foss.,  plate  v,  figs.  6,  6  a,  6). 
It  differs  widely  in  surface  characters.  I  know  of  no  American  species 
with  which  to  compare  it. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon-road 
Canon,  Eureka  District,  Nevada. 


Pterinopecten  Spio,  n.  sp. 
Plate  viii,  figs.  1, 1  a. 

Outline,  including  the  ears,  broadly  truncato-ovate.  Left  valve  de- 
pressed convex.  Hinge-line  nearly  as  long  as  the  greatest  width  of  the 
shell  below.  Anterior  ear  small,  separated  more  sharply  from  the  body 
of  the  shell  than  is  usual  in  the  genus;  sinus  rounded;  posterior  ear  large 
and  not  very  distinctly  separated  from  the  body  of  the  shell.  Beak  small, 
abruptly  pointed,  and  situated  nearly  on  the  anterior  third  of  the  length  of 
the  hinge-line. 

Surface  marked  by  about  20  linear,  radiating  costae,  with  inter-spaces 
greater  than  the  width  of  the  costse,  in  which  faintly-defined  costae  are 
sometimes  shown ;  concentric  lines  of  growth  occur,  and  under  peculiar 
conditions  of  preservation,  as  shown  in  fig.  1  of  plate  viii,  form  a  reticu- 
lated structure  with  the  radiating  costae. 

Dimensions :  height  of  an  average  specimen,  15mm;  width,  18mm;  con- 
vexity of  left  valve,  2mm  to  3mm. 

In  outline  and  the  form  of  the  wings  this  species  approaches  that  of 
Pterinopecten  exfoliatus  Hall,  of  the  Devonian  of  New  York  (Pal.  N.  Y.,  vol. 
v,  pt.  1,  p.  61,  1884),  more  nearly  than  to  any  other  species  known  to  me. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


234  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Genus  PTERINEA  Goldfuss. 

Pterinea  Piutoensis,  n.  sp. 
Plate  xix,  fig.  10. 

Shell  very  small;  body  part  obliquely  elongate,  narrowing  towards 
the  beak,  which  extends  a  little  above  the  hinge-line.  The  anterior  ear  is 
small,  rounded  in  front,  and  somewhat  compressed;  posterior  ear  large, 
compressed,  extending  beyond  the  posterior  extremity  of  the  valve,  pointed 
at  the  end,  and  slightly  sinuous  behind.  The  body  of  the  valve  ranges  at 
an  angle  of  about  40°  with  the  cardinal  margin. 

Surface  marked  by  strong  concentric  striae. 

This  little  shell  has  a  length  of  10mm  on  the  cardinal  line  and  a  height 
at  right  angles  to  this  of  6mm.  It  is  unlike  any  species  known  to  me  occur- 
ing  at  this  horizon. 

The  generic  reference  to  Pterinea  is  made  in  the  absence  of  any 
knowledge  of  the  interior  characters.  It  is  very  probable  that  it  belongs 
to  the  genus  Actinopera,  but  with  the  material  at  hand  this  cannot  be  deter- 
mined. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
northeast  side  of  canon  north  of  Pinto  Peak,  Eureka  District,  Nevada. 


Genus  LEPTODESMA  Hall. 

Leptodesma,  sp.  ? 

Two  species  of  this  genus  are  represented  in  the  collections  from  the 
lower  portion  of  the  Carboniferous.  One  is  quite  strongly  marked,  and  is 
allied  to  Leptodesma  Rogersi  Hall,  of  the  Hamilton  Group  of  New  York, 
and  the  other  to  L.  complanatum  Hall,  from  the  Chemung  Group,  New  York 
(See  Pal.  N.  Y.,  vol.  v,  pt.  1,  pp.  1 76,  227).  Each  is  represented  by  a  single, 
not  very  well-preserved  specimen,  which  renders  a  specific  identification 
very  uncertain  and  unsatisfactory. 


FOSSILS  OF  THE  CARBONIFEROUS. 


235 


Genus  PTYCHOPTERIA  Hall. 

Ptychopteria  protoforme,  u.  sp 
Plate  viii,  tig.  5. 

Shell  obliquely  elongate,  narrowing  anteriorly;   posterior  ear  broad 
and  straight,  anterior  ear  short;  beak  anterior,  obtusely  rounded;  hinge 
line  long,  but  not  quite  equaling  the  greatest  width  of  the  shell  below. 

Surface  marked  by  obscure  lines  of  growth. 

Interior  characters  unknown. 

Dimensions:  height,  12^ ;  greatest  breadth,  20mm;  convexity  of  left 
valve,  2mm  to  3mm. 

The  outline  of  this  species  is  more  nearly  like  that  of  Ptychopteria 
Proto  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  1,  p.  129,  1884)  than  that  of  any  other 
species  known  to  me.  The  ear  is  not  as  broad,  and  it  also  terminates  in  a 
more  acute  angle  with  the  hinge-line,  in  this  respect  resembling  P.  sinuosa 
Hall  (loc.cit.  p.  130). 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Caflon,  Eureka  District,  Nevada. 


Genus  PINNA  Linnaeus. 

Pinna  inexpectans,  n.  sp. 

Plate  xix,  fig.  11. 

Shell  elongate,  lanceolate,  over  four  times  longer  than  wide;  section 
elliptical,  valves  not  very  convex;  ventral  and  dorsal  margins  straight  or 
slightly  convex.  The  dorsal  or  cardinal  margin  is  a  little  thickened  and 
with  a  well-defined  rounded  rim  at  the  edge. 

Surface  marked  by  strong  ridges  subparallel  to  the  dorsal  and  ventral 
margins;  they  are  more  or  less  flexuous,  and  while  obsolete  on  the  upper 
portion  of  some  examples,  are  present  on  the  entire  width  of  the  shell  in 
others.  A  few  obscure  concentric  lines,  parallel  to  the  posterior  margin, 
cross  the  radiating  plications. 


236  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

This  species  is  allied  to  Pinna  Missouriensis  Swallow  (Trans.  St.  Louis 
Acad.  Sci.,  vol.  ii,  p.  97,  1863),  but  from  the  description  of  that  species  it 
appears  to  differ  in  form  and  surface  markings.  It  differs  from  P.flexicostata 
McCoy  (Brit.  Pal.  Foss.,  p.  499),  in  being  more  elongate,  and  also  in  hav- 
ing the  radiating  plications  on  the  entire  lower  half  of  the  valves. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon-road  Canon, 
Eureka  District,  Nevada. 


Pinna  consimilis,  n.  sp. 
Plate  xx,  fig.  13. 

Valves  elongate,  about  three  and  one-half  times  longer  than  the  width 
at  the  posterior  end;  the  upper  and  lower  margins  converging  at  an 
angle  of  20°  towards  the  beaks,  where  the  shell  is  pointed  and  subcylin- 
drical,  the  section  becoming  more  and  more  elliptical  toward  the  posterior 
end,  which  is  slightly  and  obliquely  rounded  ;  cardinal  margin  a  little  thick- 
ened and  with  a  narrow,  well-defined,  rounded  rim  or  cardinal  ridge. 

Surface  marked  by  concentric  lines  of  growth;  otherwise  smooth. 

The  description  is  drawn  from  a  small  specimen  llcm  in  length,  but 
fragments  of  individuals  of  twice  the  size  were  found.  The  species  is  allied 
to  P.  spatula  McCoy  (Brit.  Pal.  Foss.,  p.  499),  but  differs  in  being  less  elon- 
gate in  proportion  to  the  width,  the  outline  being  more  that  of  the  plicated 
species,  P.  flexicostata  McCoy  (loc.  cit.,  p.  499).  I  know  of  no  closely  related 
American  species,  P.  subspatulata  Worthen  (Geol.  Surv.  Ill ,  vol.  vi,  p.  524), 
being  a  much  more  elongated  form. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  with  the 
preceding  species,  and  also  on  the  northeast  side  of  the  canon  north  of  Pinto 
Peak,  Eureka  District,  Nevada.  Also  at  about  the  same  horizon  on  the 
west  slope  of  Mokomoke  Ridge,  White  Pine  District,  Nevada. 


FOSSILS  OF  THE  CAKBONIFEKOUS. 


237 


Genus  MYALINA  De  Koninck. 

Myalina  congeiieris,  n.  sp. 
Plate  xix,  fig.  6 ;   plate  xxii,  fig.  10. 

Shell  oblong,  the  height  being  twice  the  width  even  in  the  broad  ex- 
amples; hinge  line  straight  and  ranging  at  an  angle  of  60°  with  the  nearly 
straight  anterior  margin;  base  narrow,  but  rather  broadly  rounded,  poste- 
rior very  broadly  rounded,  curving  slightly  inward  towards  the  cardinal 
line.  General  surface  of  the  valves  strongly  convex  towards  the  front 
border,  and  beaks  becoming  more  depressed  on  the  posterior  portion.  Sur- 
face of  both  valves  marked  by  slightly  imbricated  lamellae  of  growth. 

The  specimen  illustrated  is  more  narrow  than  a  right  valve  associated 
with  it  that  has  all  the  essential  characters  of  the  species.  Its  specific  rela- 
tions are  with  Myalina  angulata  M.  and  W.  (Geol.  Surv.  111.,  vol.  ii,  p.  300), 
from  which  it  differs  in  having  a  more  obtuse  angle  at  the  union  of  the  car- 
dinal and  anterior  margins  and  a  less  oblique  anterior  margin.  It  is  in  out- 
line intermediate  between  M.  angulata  and  M.  subquadrata  Shumard  (Geol. 
Surv.  Missouri.,  vol.  i,  pt.  2,  p.  207,  1855);  Myalina  Apacliesi  Marcou  (Geol. 
N.  Amer.,  p.  44)  may  possibly  be  a  closely  allied  species,  but  with  the  descrip- 
tion and  figure  given  by  its  author  this  cannot  be  determined.  Compare, 
also,  M.  St.  Ludovica  Worthen  (Geol.  Surv.  111.,  vol.  v,  p.  540). 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
on  the  w£st  slope  of  Richmond  Mountain,  Eureka  District,  Nevada. 


Myalina  Nemesis,  n.  sp. 
Plate  xix,  fig.  5;  plate  xxii,  fig.  7. 

Shell  subovate  to  subquadrangular,  depressed  convex,  base  broadly 
rounded;  anterior  margin  slightly  concave  or  straight,  posterior  outline 
broadly  rounded  and  meeting  the  hinge-line  at  an  obtuse  angle.  Hinge 
straight,  shorter  than  the  greatest  width,  and  ranging  at  nearly  right  angles 
to  the  longitudinal  axis  of  the  shell.  Beaks  terminal  and  directed  obliquely 
forward. 


238  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Surface  marked  by  concentric  undulations  of  growth. 

The  original  type  of  this  species  is  the  elongate  compressed  left  valve 
illustrated  on  plate  xix,  fig.  5.  Subsequently  several  specimens  of  the  right 
valve  were  obtained  from  the  same  locality  that  show  more  nearly  the  true 
outline  of  the  shell.  The  hinge-line  varies  in  length,  as  do  the  relative  pro- 
portions of  the  height  and  width  of  the  valves,  but  these  differences  do  not 
prevent  the  union  of  the  several  examples  under  one  species. 

In  outline  some  of  the  shells  approach  Myalina  crtnpla,  M.  and  H.  (Name 
proposed  in  description  of  species,  Pal.  Upper  Missouri,  p.  33). 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group  in 
the  canon  northeast  of  Pinto  Peak,  Eureka  District,  Nevada. 


Myaliua  Nessus,  a.  sp. 

Plate  xxii,  figs.  8,  8a. 

Shell  large,  subquadrate,  narrowing  towards  the  base,  higher  than  wide, 
compressed  posteriorly,  becoming  somewhat  convex  on  the  umbonal  slopes. 
Hinge  straight,  fully  equalling,  if  not  exceeding,  the  greatest  width  of  the 
valves,  and  ranging  at  nearly  right  angles  to  the  vertical  axis  of  the  shell 
Beaks  terminal  and  directed  obliquely  forward. 

Surface  marked  by  concentric  lamellaB  and  undulations  of  growth. 

Interior  characters  unknown. 

Dimensions:  height  of  large  specimen,  10cm;  width,  about  7om. 

In  size  this  species  approaches  Myalina  ampla  M.  and  H.  (Pal.  Upper 
Missouri,  p.  38,  1855),  and  fully  equals  M.  suJbquadrata  Shumard  (GeoL 
Surv.  Missouri,  vol.  1,  pt.  2,  p.  207, 1855).  It  differs  from  the  former  species 
in  the  outline  of  the  posterior  side  and  in  the  narrowing  of  the  lower  portion 
of  the  shell,  and  also  in  the  direction  of  the  umbonal  slope.  The  same  dif- 
ferences exist  between  it  and  M.  subquadrata. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CAEBONIFEEOCTS. 


239 


Genus  MODIOLA  Lamarck. 

Modiola  ?  Nevadensis,  n.  sp. 

Plate  xix,  fig.  8. 

Shell  thin,  transversely  elongate,  narrow  anteriorly,  expanding  gradu- 
ally to  the  greatest  height  at  a  point  back  of  the  center;  anterior  end 
narrow  and  abruptly  rounded;  basal  margin  but  little  curved  except  pos- 
teriorly; posterior  end  somewhat  narrowly  rounded,  and  then  sloping 
obliquely  upward  and  forward  to  its  union  with  the  nearly  straight  car- 
dinal line.  Beaks  small,  depressed,  anterior.  General  surface  rather 
strongly  convex  anteriorly,  and  also  backward  along  the  broadly-rounded 
umbonal  ridge. 

Surface  with  fine  concentric  lines  of  growth. 

With  the  single  valves,  and  without  specimens  showing  the  hinge 
structure,  the  generic  reference  is  more  or  less  doubtful.  The  specimen 
illustrated  has  been  accidentally  compressed  anteriorly,  the  basal  margin 
having  been  pushed  down  and  beneath  its  true  position. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
the  low  hills  south  of  Newark  Mountain  by  the  side  of  Pinto  Creek,  Eureka 
District,  Nevada. 


Genus  MODIOMOBPHA  HalL 

Modiomorpha  ambigua,  n.  sp. 
Plate  xx,  fig.  1. 

Shell  rather  below  the  medium  size,  transverse  and  subquadrate  for- 
ward to  the  line  of  the  beaks,  in  front  of  which  it  contracts  rapidly  to  a 
rather  narrow,  rounded  lobe;  beaks  small,  and  situated  on  the  anterior 
third;  hinge-line  slightly  arcuate;  posterior  end  broadly  rounded  to  the 
nearly  transverse  basal  margin,  which  is  a  little  curved  towards  the  anterior 
lobe. 

Surface  marked  by  faint  concentric  strise  and  a  few  stronger  lines  of 
growth. 


240  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

There  is  some  doubt  attending  the  reference  of  this  species  to  the  genus 
Modiomorpha,  as  the  hinge  structure  and  muscular  impressions  are  unknown; 
but  in  the  absence  of  these  characters  the  general  form  of  the  shell  allies 
it  to  that  genus. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-cafion-road 
Canon,  Eureka  District,  Nevada. 


Modiomorpha  f  desiderata,  n.  sp. 
Plate  xx,  fig.  3. 

Shell  of  medium  size;  transverse,  roughly  suboval;  beaks  small,  com- 
pressed, and  situated  within  the  anterior  third,  the  portion  of  the  shell  in 
front  of  them  contracting  quite  rapidly  and  becoming  abruptly  rounded  in 
front;  the  posterior  end  is  broken  away,  but,  from  the  direction  of  the 
lines  of  growth,  it  was  probably  somewhat  broadly  rounded.  The  valves 
are  moderately  convex  and  the  surface  marked  by  a  few  lines  of  growth. 

The  nearest  allied  species  appears  to  be  Modiomorpha  Hyalea  Hall 
(Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations,  pi.  xli,  fig.  28,  1883),  from 
the  Waverly  Group  of  Ohio. 

As  with  the  preceding  species  the  generic  reference  is  doubtful;  and, 
although  their  generic  relations  are  not  clearly  determined,  it  is  thought 
desirable  to  give  specific  names  to  the  well-marked  species  of  the  class 
to  which  they  belong,  as  it  is  rarely  well  represented  in  the  Carboniferous 
Group  in  the  Rocky  Mountains. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-cafion-road 
Canon,  Nevada. 

Modiomorpha  f  Fiutoensis,  n.  sp. 
Plate  xx,  fig.  2.. 

Shell  of  medium  size,  transversely  subelliptical  in  outline;  general 
surface  moderately  convex,  with  a  rounded  umbonal  slope  to  the  greatest 
posterior  extension  of  the  valve  on  the  lower  third  of  the  posterior  margin ; 


FOSSILS  OF  THE  CARBONIFEROUS. 


241 


anterior  end  contracted  and  abruptly  rounded ;  basal  margin  broadly  arcu- 
ate and  meeting  the  slightly  oblique  posterior  line  so  as  to  form  a  rounded 
angle  ;  cardinal  margin  nearly  straight  and  forming  an  obtuse  angle  at  its 
union  with  the  posterior  margin. 

Surface  ornamented  by  numerous  concentric  striae. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
northeast  side  of  canon  north  of  Pinto  Peak,  Eureka  District,  Nevada. 


Genus  NUCULA  Lamarck. 

Nucula  insularis,  n.  sp. 
Plate  xx,  fig.  14. 

Shell  transverse,  broadly  and  irregularly  ovate,  strongly  convex,  and 
with  the  beaks  prominent  and  incurved;  anterior  end  contracted  and 
rounded  somewhat  abruptly,  the  posterior  end  more  broadly  rounded  and 
the  basal  line  still  more;  the  point  of  union  of  the  two  latter  is  almost 
subangular,  the  posterior  margin  sloping  upward  somewhat  obliquely. 

Surface  marked  by  fine  concentric  striae  and  stronger  varices  of  growth. 

This  species  is  allied  to  N.  bellastriata  Conr.,  and  N.  varicosa  H.  and 
W.  (Pal.  N.  Y.,.vol.  v,  pt.  1,  Plates  and  Explanations,  pi.  xlvi,  1883),  of 
the  Hamilton  Group  of  New  York. 

Formation  and  locality. — Lower  horizon  of  the  Carboniferous  Group, 
east  slope  of  a  small  conical  hill  on  east  side  of  Secret-cafion-road  Canon, 
Eureka  District,  Nevada. 


Nucula  levatiforme,  n.  sp. 
Plate  xxii,  figs.  1,  1  a. 

Shell  very  small,  subtriangular  in  outline,  moderately  convex.     Beaks 
elevated,  incurved,  situated  on  the  anterior  half  of  the  shell. 

Surface  marked  by  fine,  strong,  concentric,  depressed  lines  of  growth. 
Interior  characters  unknown. 
16  o  D  w 


242  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

Dimensions:  height,  6mm;  width,  7mm;  convexity  or  depth  of  right 
valve,  2mm. 

This  small  species  is  more  closely  allied  in  external  form  to  Nucula  ? 
levata  Hall  (Pal.  N.  Y.,  vol.  i,  p.  150,  pi.  xxxiv,  figs.  1  a-i,  1847),  of  the 
Trenton  limestone  of  New  York  than  to  any  Carboniferous  species  that 
I  am  acquainted  with. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  conical  hill  on  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 

Genus  SOLENOMYA  Lamarck. 

Solenomya  curta,  n.  sp. 
Plate  xxii,  figs.  6,  11. 

Outline  transversely  elliptical  or  oblong-oval,  moderately  convex. 
Hinge-line  about  one-half  the  length  of  the  shell ;  beak  depressed,  situated 
at  the  anterior  third  of  the  shell. 

Surface  with  narrow  undulations  of  growth,  crossed  by  nearly  obso- 
lete, radiating,  flat  plications,  with  finer  striae  between. 

Interior  characters  unknown. 

Dimensions:  height,  2.25cm;  width,  3.75cm;  convexity  or  depth  of  left 
valve,  .5cm.  A  smaller,  more  elongate  right  valve  has  a  height  of  1.5cm,  and 
a  width  of  3cm.  With  but  one  specimen  of  the  latter  to  study  it  is  referred 
to  this  species  somewhat  provisionally,  as  there  is  no  series  of  forms  unit- 
ing it  with  the  former. 

I  know  of  no  species  with  which  this  can  be  directly  compared,  its 
shorter,  higher  form  distinguishing  it  from  described  species. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CAEBONIFEEOUS. 


243 


Genus  MACRODON  Lycett. 

Macrodon  Hamiltonae  Hall. 
Plate  xxiii,  figs.  5,  5o-c. 

Macrodon  Hamiltonce  Hall,  1870.  Prelim.  Notice  Lain.  Shells,  8vo.,  pamphlet,  p.  13. 
Idem.,  1883.  Pal.  N.  Y.,  vol.  v,  pt.  1  j  Plates  and  Explanations,  pi.  li,  figs. 
1-10. 

In  comparing  a  large  series  of  specimens  referred  to  this  species  from 
Nevada,  with  the  beautiful  illustrations  of  it  given  in  the  Paleontology  of 
New  York,  and  also  with  specimens  from  the  Hamilton  Group  of  New  York, 
I  do  not  find  sufficient  differences  on  which  to  base  a  specific  separation 
of  the  Nevada  and  New  York  shells,  although  the  former  occur  in  strata  of 
Lower  Carboniferous  age,  and  the  latter  in  the  lower  half  of  the  Devonian 
Group.  The  differences  are  in  the  outline  of  the  cardinal  margin  as  com- 
pared with  the  majority  of  the  New  York  specimens,  and  the  apparently 
thicker  shell.  The  first  is  negatived  by  the  occurrence  of  specimens  of  the 
same  outline  with  the  New  York  specimens,  and  the  second  is  owing  to  the 
condition  of  preservation,  the  macerated,  compressed  shells  of  the  Hamilton 
shales  not  preserving  the  original  structure  of  the  shell.  The  Nevada  speci- 
mens show  the  large  anterior  muscular  scar  in  the  casts,  but  not  the  lateral 
teeth  shown  in  many  of  the  New  York  examples  of  the  species. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Macrodon  truncatus,  n.  sp. 
Plate  viii,  fig.  2. 

Shell  subrhomboidal,  convex,  with  an  undefined  depression  extending 
from  the  beak  obliquely  to  near  the  center  of  the  basal  line ;  anterior  side 
rounded,  posterior  side  rounded  below,  nearly  straight  above.  Hinge-line 
straight,  nearly  as  long  as  the  greatest  width  of  the  shell  below.  Umbo 
depressed,  situated  anterior  to  the  middle  of  the  valves ;  beak  small,  in- 
curved. 


244  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

Surface  marked  by  concentric  lines  of  growth  and  numerous  fine 
radiating  costse  closely  arranged. 

Interior  characters  unknown. 

Dimensions:  height,  6°°;  width,  10mm;  convexity  of  left  valve,  3™*. 
Right  valve  unknown. 

This  litttle  shell  is  allied  to  Macrodon  parvus  W.  and  W.  (Proc.  Boston 
Soc.  Nat.  Hist,  vol.  viii,  p.  299,  1862)  of  the  Burlington  Group  of  Iowa, 
and  M.  Chemungensis  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  1  ;  Plates  and  Explana- 
tions, pi.  li,  figs.  11-16,  1883),  from  the  Chemung  Group  of  New  York. 
It  is  distinguished  from  each  by  its  short  form  and  strongly  ornamented 
surface.  The  generic  reference  is  made  on  the  general  character  of  the  ex- 
ternal shell,  as  the  hinge-line  and  internal  characters  are  unknown. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill,  on  the  east  side  of  Secret-canon- 
road  CaSon,  Eureka,  District,  Nevada. 

Genus  GEAMMYSIA  De  Verneuil. 

Grammy sia  Hannibalensis  Shumard  (Sp.). 
Plate  xx,  fig.  4. 

Altorisma  hannibalensis  Shumard,  1855.    Geol.  Surv.  Missouri,  vol.  i,  pt.  2,  p.  206,  pi. 

C,  fig.  19. 
Qrammysia  hannibalensis  Hall,  1870.    Prelim.  Notice  Lam.  Shells,  p.62. 

Hannibalensis  Meek,  1875.    Pal.  Ohio,  vol.  ii,  p.  300,  pi.  xvi,  figs.  5a-c. 

Hannibalensis  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explana- 
tions, pi.  Ixi,  figs.  23-33. 

After  comparing  the  Eureka  examples  of  this  species  with  authentic 
specimens  from  the  Waverly  sandstone  of  Ohio,  no  reasonable  doubt  re- 
mained of  their  specific  identity. 

The  species  ranges  from  the  Chemung  Group  of  New  York  to  the 
Waverly  of  Ohio,  and  at  the  base  of  the  Carboniferous  of  Iowa  and  Mis- 
souri. 

Formation  and  locality. — Carboniferous  Group,  lower  portion,  on  east 
slope  of  a  small  conical  hill  on  the  east  side  of  Secret- canon-road  Cafion, 
Eureka  District,  Nevada. 


FOSSILS  OF  THE  CABBONIFEROUS. 


245 


Grammysia  arcuata  Conrad  (Sp.) 
Plate  xx,  fig.  5. 

Posidonia  f  arcuata  Conrad,  1841.    Ann.  Eep.  Geol.  Surv.  New  York,  p.  53. 
Grammysia  arcuata  Hall,  1870.    Prelim.  Notice  Lam.  Shells,  p.  56. 

(Leptodomus  f)  arcuata  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1 ;  Plates  and 
Explanations,  pi.  Ixi,  figs.  1-9. 

Although  this  species  is  confined  to  the  Hamilton  Group  of  New  York 
and  Virginia,  as  far  as  heretofore  known,  we  are  unable  to  separate  the  Car- 
boniferous shell  from  it  on  good  specific  grounds.  Its  occurrence  at  this 
locality  and  horizon  is  not  surprising,  as  we  have  in  the  Devonian,  and  also 
at  this  same  locality,  examples  of  as  great  a  range  of  supposed  limited 
species,  e.  g.,  Pleurotomaria  nodomarginata,  Schizodus  cuneatus,  etc. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret- canon-road 
Cafion,  Eureka  District,  Nevada. 


Genus  EDMONDIA  De  Koninck. 

Edmondia  Medon,  n.  sp. 
Plate  xxiii,  fig.  6. 

Shell  transversely  subelliptical,  moderately  convex,  equivalve.  Hinge- 
line  slightly  arcuate ;  beaks  depressed,  situated  on  the  anterior  third  of  the 
shell. 

Surface  marked  by  concentric  lines  and  undulations  of  growth. 

Interior  characters  unknown. 

Dimensions  :  height,  1  5cm;  width,  2.5cm;  convexity  of  single  valve,  0.5cm. 

The  specimen  illustrated  is  the  only  well-preserved  one  we  have  of  this 
species.  In  some  respects  it  approaches  E.  Burlingtonensis  W.  and  W. 
(See  Pal.  N.  Y.,  vol.  v,  pt.  1 ;  Plates  and  Explanations,  pi.  Ixiv,  figs.  19-29, 
1883),  of  the  Burlington  limestone  of  Iowa,  and  the  Chemung  Group  of 
New  York,  differing  in  its  more  elliptical  form  and  depressed  beak. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


246  PALEONTOLOGY  OF  THE  EUBEKA  DISTRICT. 

Edmondia  f  circularis,  n.  sp. 
Plate  xxii,  fig.  9. 

Shell  large;  general  outline  broadly  ovate  or  subcircular,  moderately 
convex,  most  prominent  at  the  umbonal  region.  Hinge-line  unknown,  but 
probably  arcuate;  beaks  depressed,  curved  over  towards  the  cardinal  line. 

Surface  marked  by  concentric  lines  of  growth  as  far  as  known.  In- 
terior characters  unknown. 

Dimensions:  height,  5cm;  width,  6cm;  convexity  of  left  valve,  1.5cm. 

I  know  of  no  species  with  which  to  compare  this.  The  generic  refer- 
ence is  made  on  the  general  form  and  appearance,  as  nothing  is  known  of 
the  interior  characters. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 

Genus  PLEUROPHORUS  King. 

Pleuiophorus  Meeki,  u.  sp. 
Plate  viii,  fig.  3. 

Shell  small,  longitudinally  oblong,  widening  posteriorly;  moderately 
convex  on  the  line  of  the  umbonal  slopes  from  the  beak  to  the  postero- 
basal  margin,  forming  a  nearly  rounded  section  -from  the  basal  to  the  cardi- 
nal margin.  Hinge-line  long  and  nearly  straight,  with  a  narrow  but  well- 
defined  lunette.  Beaks  located  very  near  the  anterior  extremity. 

External  surface  of  the  shell  unknown.  The  cast  shows  5  or  6  ra- 
diating costse  and  traces  of  concentric  lines  of  growth. 

The  anterior  adductor-muscular  impression  is  bounded  by  a  rather 
strong  ridge  on  the  posterior  side;  pallial  line  simple  and  extending  to  the 
slightly-marked  posterior-adductor  muscular  scar;  teeth  unknown. 

This  species  is  more  nearly  related  to  the  English  Permian  species 
Pleurophorus  costatus  King  (Mon.  Perm.  Foss.,  plate  xv)  than  to  any  Ameri- 
can form  that  I  am  acquainted  with.  The  narrow  form  and  posterior  expan- 
sion serve  to  distinguish  it  from  described  species  of  the  genus. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CARBONIFEKOUS. 


247 


-  Genus  SANGUINOLITES  McCoy. 

In  the  absence  of  the  structure  of  the  hinge-line,  the  muscular  scars, 
and  pallial  impression  in  the  following  species,  there  is  some  uncertainty  in 
referring  them  to  this  genus,  as  in  their  general  external  appearance  they 
resemble  more  or  less  forms  referred  to  the  Modiomorphidse. 

San§uiuolites  JEdlua  H.  &  W. 

Plate  xx,  figs.  6,  7,  9. 

Sanguinolites  ceolus  Hall,  1870.    Prelim.  Notice  Lam.  Shells,  p.  46. 

?  ceolus  Meek,  1875.    Pal.  Ohio,  vol.  ii,  p.  307,  pi.  xvi,  figs.  1  a-c. 
^olus  Hall,  1883.    Pal.  N.  Y.,  vol.  v,  pt.  1,  Plates  and  Explanations, 
pi.  Ixvi,  fi^s.  31-35,  43. 

The  specimen  illustrated  by  fig.  6  is  a  typical  form  of  this  species,  cor- 
responding to  those  from  the  Waverly  sandstone  of  Ohio,  and  we  cannot 
distinguish  the  shorter,  broader  shells,  as  shown  by  figs.  7  and  9,  as  a  dis- 
tinct species,  as  there  is  a  complete  gradation  of  form  between  them,  and 
to  even  a  still  broader  variety  that  is  designated  in  the  systematic  list  as 
S.  JEolus,  var.  A  small  shell  of  this  species  from  the  same  locality  resembles 
very  closely  some  examples  of  Sanguinolites  rigidus,  an  illustration  of  which 
is  given  from  the  Devonian  .limestone  on  plate  xvi,  fig.  6. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon-road 
Canon,  Eureka  District,  Nevada 


Sanguinolites  retusus,  n.  sp. 
Plate  xx,  fig.  10. 

Shell  broad,  irregularly  ovate;  moderately  convex;  beaks  anterior, 
small  and  compressed;  umbonal  slope  distinctly  angular  and  extending 
from  the  beaks  to  the  postero-basal  angle,  the  somewhat  rapidly  sloping 
postero-cardinal  slope  being  marked  midway  by  a  slight  longitudinal  ridge. 
Cardinal  line  short  and  a  little  arcuate;  basal  line  broadly  rounded,  uniting 
posteriorly  with  the  slightly  rounded,  oblique  posterior  line  to  form  a 


248  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

rounded,  obtuse  angle,  and  rounding  up  more  rapidly  anteriorly  in  the 
more  abruptly  curved  end. 

Surface  marked  by  concentric  lines  of  growth,  and  in  well-preserved 
examples  fine  concentric  striae  are  visible. 

This  species  is  readily  distinguished  by  its  rotund  outline  from  the 
associated  species. 

Formation  and  localities. — Associated  with  the  preceding,  and  also  on 
the  northeast  slope  of  the  canon  north  of  Pinto  Peak,  Eureka  District, 
Nevada. 

Sanguinolites  simplex,  n.  sp. 
Plate  xx,  fig.  11. 

Shell  rather  above  the  average  size,  transverse,  irregularly  broad-ovate, 
beaks  small,  compressed,  and  situated  on  the  anterior  third  of  the  shell; 
umbonal  slope  angular  from  the  beak  to  the  posterior  basal  angle;  general 
surface  of  the  valves  moderately  and  regularly  convex,  except  the  postero- 
cardinal  slope,  which  falls  away  more  rapidly  from  the  umbonal  ridge;  it  is 
marked  by  a  faint,  central  longitudinal  ridge.  The  general  outline  is  not 
very  much  unlike  that  of  the  preceding  species,  except  in  the  more  pointed 
extremities  and  the  near  approach  of  the  umbonal  ridge  to  the  postero- 
cardinal  margin. 

Surface  marked  by  fine  concentric  strise,  and  a  few  stronger  lines  of 
growth. 

Formation  and  locality. — Lower  horizon  of  the  Carboniferous  Group, 
eastern  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-caflon-road 
Canon,  Eureka  District,  Nevada. 


Sanguinolites  Salteri,  n.  sp. 
Plate  xx,  fig.  12. 

Shell  rather  small,  transversely  elongate,  nearly  three  times  as  long  as 
high;  cardinal  and  basal  margins  subparallel  or  slightly  diverging  on  the 
posterior  half  of  the  shell;  beak  small,  depressed,  and  situated  near  the 
anterior  end,  which  is  narrow,  short,  and  abruptly  rounded;  basal  margin 


FOSSILS  OF  THE  CARBONIFEROUS. 


249 


nearly  transverse  along  the  center,  curving  up  rather  abruptly  anteriorly, 
and  more  gently  at  the  posterior  end;  posterior  line  abruptly  rounded  at 
the  point  of  greatest  extension  on  a  line  with  the  center  of  the  shell,  above 
which  it  curves  forward  to  the  straight  cardinal  line.  Valves  marked  by 
several  distinct,  but  not  prominent,  ridges  on  the  postero-cardinal  slope. 

Surface  ornamented  by  fine  concentric  striae,  and  a  few  obscure  lines 
of  growth. 

Formation  and  locality. — Lower  horizon  of  the  Carboniferous  Group, 
eastern  slope  of  a  small  conical  hill  on  east  side  of  Secret-cafion-road 
Can" on,  Eureka  District,  Nevada. 

Sanguinolites  f  Naenia,  n.  sp. 
Plate  xix,  fig.  9. 

Shell  small,  transversely  elongate,  the  height  being  one-half  the  length; 
beaks  small,  depressed,  and  situated  on  the  anterior  third;  anterior  end  nar- 
row, somewhat  elongate  and  so  abruptly  rounded  as  to  be  almost  angular; 
basal  line  slightly  sinuate  midway  and  curving  up  at  each  end;  posterior 
end  broadly  rounded;  cardinal  line  nearly  straight  The  general  surface 
of  the  valves  is  moderately  convex,  with  a  slight  umbonal  ridge  extending 
from  the  beak  to  the  postero-basal  curve,  and  also  a  rather  broad,  shallow 
mesial  depression. 

Surface  marked  by  several  well-defined,  concentric  undulations  of 
growth. 

Formation  and  locality. — Lower  horizon  of  the  Carboniferous  Group, 
eastern  slope  of  a  small  conical  hill  on  east  side  of  Secret-canon-road 
Canon,  Eureka  District,  Nevada. 


Sanguinolites  striatus,  n.  sp. 
Plate  xxiii,  fig.  7. 

Shell  transversely  elongate-oval,  compressed  convex,  posterior  umbonal 
slope  angular.  Cardinal  line  long,  straight.  Beak  appressed,  situated  at 
about  the  anterior  third. 


250  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

Surface  marked  by  strong  concentric  strise  that  curve  up  rather 
abruptly  in  crossing  the  angular  umbonal  ridge. 

Interior  characters  unknown. 

There  are  three  specimens  preserving  the  anterior  portions  of  the  shell, 
but  none  showing  the  entire  outline.  The  specimen  illustrated  has  the 
form  we  have  considered  as  belonging  to  the  genus  Sanguinolites. 

The  strongly  striated  surface  distinguishes  it  from  described  species 
known  to  me. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


Genus  MICRODON  Conrad. 

(CYPRICARDELLA  Hall.) 

Microdon  (Cypricardella)  connatus,  n.  sp. 

Plate  xxiv,  figs.  5,  5«. 

Shell  transversely  subovate  or  subrhomboidal,  moderately  convex. 
Hinge-line  about  two-thirds  the  length  of  the  shell.  Beaks  small,  depressed, 
and  situated  on  the  anterior  third  of  the  shell. 

Surface  marked  by  rather  distinctly  defined  concentric  strise. 

The  interior  cast  shows  an  anterior  adductor  muscular  scar  of  medium 
size,  also  an  undefined  depression  extending  from  the  beak  obliquely  back- 
ward on  the  line  of  the  umbonal  ridge. 

Dimensions:  height,  1.75cm;  length,  3cm;  convexity  of  the  two  valves 
united,  lcm. 

In  form  this  species  approaches  very  closely  to  Microdon  ((7.)  gregarius 
Hall,  and  in  surface  characters  M.  (C.)  bellistriatus  Conrad  (Pal.  N.  Y.,  vol. 
v,  pt.  I ;  Plates  and  Explanations,  pis  Ixxiii,  Ixxiv,  1883).  While  differing 
from  both,  it  combines,  in  a  measure,  the  specific  characters  of  each. 

The  reference  of  this  and  also  the  Devonian  M.macrostriatus  (ante,p.  180) 
to  the  genus  Microdon  is  tentative.  Professor  Hall  proposed  the  name  Eodon 
as  a  substitute  for  Microdon,  as  the  latter  had  already  been  used  for  a  genus 


FOSSILS  OF  THE  CARBONIFEROUS. 


251 


of  fishes  and  a  genus  of  insects  (Miller's  Cat.  Pal.  Foss.,  Addenda,  p.  244, 
1877).  In  the  Paleontology  of  New  York  (vol.  v,  part  1;  Plates  and  Ex- 
planations, p.  18,  1883),  a  second  generic  name  is  placed  between  Microdon 
and  Eodon,  viz,  Microdonella.  Professor  Hall  previously  described  the  genus 
Cypricardella  for  similar  forms  from  the  Warsaw  limestone  (see  remarks  by 
Mr  Whitfield,  Bull.  Amer  Mus.  Nat  Hist,  vol.  i,  No.  3,  p.  63),  and  if  Micro- 
don is  dropped  Cypricardella  will  have  to  be  substituted. 

Formation  and  localities. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  the  cafion  north  of  Pinto  Peak,  and  also  on  the  east  slope  of  a  small 
conical  hill  on  the  east  side  of  Secret-canon-road  Canon,  Eureka  District, 
Nevada. 


Genus  CARDIOLA  Broderip. 

Cardiola  ?  filicostata,  n.  sp. 
Plate  xxii,  figs.  4$  4  a. 

Shell  obliquely  oval,  moderately  convex.  Beak  somewhat  elevated, 
small  and  incurved. 

Surface  marked  by  fine,  radiating,  slightly  irregular,  elevated  striae, 
and  a  few  concentric  lines  of  growth. 

Interior  characters  unknown. 

Dimensions:  height,  1.5cm;  width,  2cm;  convexity  or  depth  of  left 
valve,  0.5cm. 

The  generic  reference  is  doubtful,  owing  to  the  absence  of  the  interior 
characters,  and  also  the  strong  surface  costse,  so  characteristic  of  Cardiola. 
The  only  related  species  referred  to  the  genus  is  Cardiola  transversa  Hall 
(Pal.  N.  Y.,  vol.  v,  pt,  1 ;  Plates  and  Explanations,  pi.  Ixx,  figs.  12-15). 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Cation,  Eureka  District,  Nevada. 


252  PALEONTOLOGY  OF  THE  EUKEKA  DISTEICT. 

Genus  SCHIZODUS  King. 
Schizodus  cuneatus  Meek. 

Plate  xx,  fig.  8. 
Schizodus  cuneattis  Meek,  1875.    Pal.  Ohio,  vol.  ii,  p.  336,  pi.  xx,  fig.  7. 

There  does  not  appear  to  be  any  points  of  specific  difference  between 
the  Ohio  shell  illustrated  by  Mr.  Meek  and  the  examples  of  this  species 
from  Nevada.  The  latter  are  proportionally  a  little  narrower,  but  this  may 
be  owing  to  the  state  of  preservation,  as  the  Ohio  shell  is  compressed  in  a 
shale,  and  the  Nevada  specimens  retain  their  natural  convexity  and  outline. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  group,  on 
the  eastern  slope  of  a  small  conical  hill  on  the  east  side  of  Secret  canon- 
road  Canon,  Eureka  District,  Nevada. 

Schizodus  deparcus  n.  sp. 
Plate  xxii,  fig.  5. 

Shell  large,  transversely  suborbicular,  moderately  convex;  urnbonal 
ridge  rounded  and  passing  into  the  postero-dorsal  slope  without  any  per- 
ceptible angle  being  developed.  Beak  small,  elevated,  incurved,  and  sit- 
uated a  little  anterior  to  the  center  of  the  shell. 

Surface  smooth  as  far  as  known,  except  a  few  radiating  lines  on  the 
postero-dorsal  slope. 

Anterior  muscular  scar  not  large,  ovate  in  outline ;  posterior  scar  elon- 
gate, and  crossed  longitudinally  by  two  slightly  depressed  lines,  probably 
from  the  radiating  lines  of  the  postero-dorsal  slope  of  the  shell.  Pallial  line 
simple. 

Dimensions:  height,  4.25  m;  width,  f,cm;  convexity  or  depth  of  right 
valve,  1.5cm.  In  size  this  species  approaches  Scliizodus  cuneatus  (ante).  It 
differs  in  being  less  erect,  less  angular  in  outline,  and  in  having  a  smooth 
surface. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone on  east  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CABBONIFEKOUS. 


253 


Schizodus  curt i forme,  n.  sp. 
Plate  xxii,  figs.  3,  3  a. 

Shell  small,  subrhomboidal,  moderately  convex;  posterior  dorsal  region 
back  of  the  umbonal  ridge  compressed  and  cuneate;  umbonal  slope  dis- 
tinctly angular  from  the  beak  to  the  postero-basal  margin;  anterior  slope 
rather  abrupt  to  the  anterior  margin.  Beak  elevated,  incurved,  and  situated 
a  little  anterior  to  the  center. 

Surface  of  the  cast  with  a  few  indications  of  concentric  lines  of  growth. 

Interior  characters  unknown. 

Dimensions:  height,  1.5cm;  width,  1.75cm;  convexity  or  depth  of  right 
valve,  .5cm. 

This  little  species  is  related  to  Schizodus  curtus  M.  and  W.  (Geol.  Surv. 
111.,  vol.  v,  p.  582),  and  S.  Rossicus  De  Vern.  (Russ.  and  Ural  Mts.,  p.  309),  but 
can  scarcely  be  referred  to  either  specifically. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Cafion,  Eureka  District,  Nevada. 


Schizodus  Piutoensis,  n.  sp. 
Plate  xxii,  figs.  2,  2  a. 

Shell  about  the  average  size  of  species  of  the  genus;  outline  obliquely 
subrhomboidal;  base  strongly  arcuate;  umbonal  slope  distinctly  angular, 
with  the  posterior  side  flattened;  general  surface  moderately  convex,  curv- 
ing evenly  over  the  central  portions  anterior  to  the  umbonal  angle  and  then 
more  abruptly  down  to  the  anterior  margin.  Beaks  elevated,  incurved,  and 
placed  on  the  anterior  third  of  the  shell. 

Surface  of  cast  showing  a  few  lines  of  growth. 

Dimensions:  height,  2cm;  width,  2.25cm;  convexity  or  depth  of  left 
valve,  0.5cm. 

Some  of  the  examples  are  more  oblique,  and  have  the  appearance  of 
being  more  erect,  owing  to  the  greater  curvature  of  the  basal  margin.  This 
is  shown  in  the  illustration  of  the  right  valve. 


254  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

In  comparing  with  Schizodus  cuneus  Hall,  from  the  Waverly  Group 
(Pal.  N.  Y.,  vol.  v,  pt.  1;  Plates  and  Explanations,  pi.  Ixxv,  figs.  27-30),  a 
strong  resemblance  is  apparent,  the  Nevada  shell  differing  only  in  its  more 
robust  form  and  in  the  strongly  arcuate  basal  and  anterior  margins. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  the  canon  northeast  of  Pinto  Peak,  Eureka  District,  Nevada. 

GASTEROPODA. 

Genus  PLATYCERAS  Conrad. 

Platyceras  occidens,  n.  sp. 

Plate  xxiv,  tigs.  9,  9 a. 

Shell  obliquely  subconical,  apex  minute  and  strongly  incurved,  the 
nucleus  making  about  one  volution  and  then  rapidly  expanding;  the  dor- 
sum  is  somewhat  abruptly  rounded  but  not  carinate;  the  right  side  is  gently 
and  evenly  convex  to  the  rounded  angle  formed  by  the  union  with  the 
front ;  the  left  side  is  more  abruptly  convex,  and  curves  forward  impercep- 
tibly into  the  anterior  surface.  Aperture  subtriangular  in  outline  with  the 
peristome  sinuous. 

Surface  marked  by  fine,  well-defined,  undulating  striae  of  growth. 

This  is  a  small  and  very  pretty  species.  It  may  be  compared  with 
some  forms  of  Platyceras  carinatum  Hall  (Pal.  N.  Y.,  vol.  v,  pt.  2,  p.  5,  pi. 
ii,  figs.  12-29)  of  the  Devonian. 

Formation  and  locality, — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 

Platyceras  Piso,  n.  sp. 
Plate  xxiv,  figs.  7,  7  a,  b. 

Shell  obliquely  and  strongly  arcuate;  apex  minute,  incurved,  making 
about  one  volution;  body-whorl  expanding  rather  rapidly  at  first  and  then 
very  gradually  to  the  aperture ;  dorsum  rounded ;  sides  and  dorsum  with 
seven  or  eight  slight  longitudinal  plications;  aperture  broadly  subovate 
with  the  peristome  sinuous. 


FOSSILS  OF  THE  CARBONIFEROUS. 


255 


Surface  covered  with  fine,  undulating  strise  of  growth  that  are  crowded 
together  irregularly,  forming  slight  concentric  undulations. 

The  arcuate  form  of  the  body-whorl  distinguishes  this  species  from 
Pldtyceras  acutirostris  Hall  (Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  665,  pi.  xxiii, 
fig.  1-1)  of  the  Lower  Carboniferous  of  Indiana,  etc.,  the  most  nearly  allied 
species. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  north  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Genus  PLATYOSTOMA  Conrad. 

Platyostoma  iuornatum  n.  sp. 

Plate  xxiv,  figs.  3,  3  a. 

Shell  subglobose;  spire  elevated  above  the  body  whorl ;  volutions  three 
or  four,  and  perhaps  a  fifth  very  minute  one,  that  is  not  preserved  in  the 
specimen  illustrated.  The  outer  volution  expanding  towards  the  aperture, 
but  scarcely  ventricose;  aperture  vertically  ovate  or  subrhomboidal;  the 
columellar  lip  appears  to  have  been  reflexed. 

The  few  fragments  of  the  outer  shell  that  are  preserved  show  it  to 
have  been  nearly  if  not  quite  smooth. 

This  species  resembles  some  forms  of  Platyostoma  lineatum  (ante,  p.  185) 
of  the  Devonian  of  New  York. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  the  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Genus  EUOMPHALDS  Sowerby. 

Euomphalus  (Straparollus)  subrugosus  M.  &  W. 
Plate  xviii,  fig.  19. 

Euomphalus  rugosus  Hall,  1858.    Geol.  Surv.  Iowa,  vol.  i,  pt.  2,  p.  722,  pi.  xxix,  figs. 

14a-c.     (Not  Euomphalus  rugosus  Sowerby,  1849.) 
Serpula  \  Spirorbis)  planorbitcs  Geinitz,  1866.     Carb.  uud  Dyas  in  Nebraska,  p.  2,  pi. 

i,  fig.  6,  (not  of  Munster). 


256  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

8traparollu8  (Euomphalus)  rugosus  Meek,  1872.    U.  S.  Geol.  Surv.  Nebraska,  p.  230 

pi.  vi,  figs.  5  a,  6;  pi.  xi,  figs.  4 a,  &. 
Straparollus  (Euomplmlus)  submgosus  Meek  &  Worthen,  1873.    Geol.  Surv.  Illinois, 

vol.  v,  p.  607,  pi.  xxix,  figs.  11  a-c. 

The  example  of  this  species  in  the  collection  has  the  essential  features 
observed  in  the  specimens  from  the  Coal  Measures  of  Illinois,  Nebraska,  etc., 
and  no  specific  differences  are  recognized  between  the  form  from  Nevada 
and  those  of  the  Mississippi  Valley  region. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  on 
the  east  slope  of  a  small  conical  hill  on  the  east  side  of  the  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 

Genus  BELLEROPHON  Montfort. 

Belferophon  majusculus,  n.  sp. 
Plate  xxiii,  figs.  1,  la;  plate  sxiv,  fig.  6. 

Shell  thick  and  strong,  very  large,  subglobose;  body  volution  subglo- 
bose,  expanded  a  little  at  the  aperture,  marked  by  a  well-defined  median 
carina ;  outer  lip  with  a  strong  sinus  in  front,  rounded  at  the  sides,  somewhat 
reflexed  and  greatly  thickened  over  the  umbilical  areas,  entirely  concealing 
the  openings.  Inner  margin  of  the  columellar  lip  very  much  thickened, 
boss-like,  extending  out  into  the  aperture  and  giving  the  latter  a  broadly 
subreniform  outline;  the  outer  lip  probably  extended  over  a  portion  of  the 
columellar  lip,  but  the  specimens  at  hand  do  not  show  this  clearly. 

Surface  characters  mostly  obliterated,  a  few  of  the  stronger  lines  or 
wrinkles  of  growth  alone  remaining;  these  curve  gently  forward  between 
the  dorsal  carina  an.d  the  umbilicus. 

Dimensions:  greatest  length,  12cm;  breadth  at  umbilicus,  7.5om;  at  ap- 
erture, llcm.  Aperture,  3.5cm  by  7.5cm  in  a  specimen  10cm  long,  by  6.5om 
wide  at  the  umbilicus. 

This  large  Bellerophon  is  most  nearly  related  to  Bellerophon  costatus 
Sowerby,  as  figured  by  De  Koninck  (Anm.  Foss.,  plate  xxvi,  fig.  2  a-e).  It 
differs  in  the  direction  of  the  lines  of  growth,  form  of  aperture,  and  the 
thickening  of  the  columellar  lip.  Bellerephon  crassus  M.  and  W.  (Geol.  Surv. 
111.,  vol.  ii,  p.  385,  pi.  xxxi,  figs.  16  a,  &),  from  the  Lower  Coal  Measures  of 


FOSSILS  OF  THE  CARBONIFEROUS. 


257 


Illinois,  is  the  largest  American  species  of  the  genus.     It  varies  materially 
from  Z>.  majiisculus  in  the  character  of  the  columellar  lip. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  a  canon  a  little  north  of  Pinto  Peak,  Eureka  District,  Nevada. 


.CHAMBER 


•SHELL 


FIG.  3.— Section  of  the  large  specimen  figured  on  plate  xxiii,  fig.  6.  The  chamber  of  the  interior 
whoils  is  filled  iu  with  calcite,  which  leaves  only  the  outer  whorl  clearly  outlined,  including  a  section 
of  iff  chamber. 

Bellerophon  textilis  Hall  ? 
Plate  xviii,  fig.  1H. 

Bellerophon  canceUatus  Hall,  1850,     Trans.  Albany  lust.,  vol.  iv,  p.  31  (not  B.  cancel- 

latits  Hall,  1847,  Pal.  X.  Y.,  vol.  i,  p.  307). 
Bellerophon  textilis  Hall,  1877.     Proposed  instead  of  />.  cttnccllatus  Hall  (preoccupied). 

Miller's  Cat.  Anier.  Pal.  Foss.,  p.  243. 

Our  specimens  are  all  more  or  less  crushed  and  distorted,  but  com- 
17  c  n  w 


258  PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 

parisons  with  examples  of  B.  textilis  from  the  Warsaw  limestone  of  Indiana 
exhibit  strong  specific  resemblances  which,  in  the  absence  of  more  perfect 
specimens  to  show  possible  differences,  place  the  Eureka  shell  in  the  same 
species. 

Two  other  species  occur  in  the  same  beds;  one  is  like  B.  sublcevis  Hall, 
1856  (Trans.  Albany  Inst.,  vol.  iv,  p.  32),  of  the  Warsaw  limestone,  and  the 
other  is  of  the  character  of  B.  ellipticus  McChesney  (see  Trans.  Chicago 
Acad.  Sci.,  vol.  i,  p.  44),  from  the  Coal  Measures  of  Illinois,  but  there  is  not 
sufficient  material  to  decide  conclusively  upon  the  specific  relations. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
east  side  of  Secret-canon-road  Canon  on  east  slope  of  a  small  conical  hill, 
Eureka  District,  Nevada. 

Genus  LOXONEMA  Phillips. 

Loxonema  bella,  n.  sp. 
Plate  xxiv,  figs.  1,  la. 

Shell  small  elongate-conical ;  spire  elevated,  tapering  to  an  acute  point. 
Volutions  fourteen  to  fifteen,  very  slightly  convex,  increasing  gradually  in 
size  to  the  last  one,  which  is  a  little  enlarged  and  rather  abruptly  rounded 
below  the  middle. 

Suture  close  but  not  deep.  Aperture  subovate  or  subrhombic,  longer 
than  wide. 

Surface  smooth  to  the  unaided  eye,  but  under  a  strong  magnifying 
glass  shows  fine  concentric  striae  of  growth  that  curve  slightly  forward ;  at 
the  suture  these  are  a  little  stronger. 

Dimensions:  length,  18mm;  breadth  of  body  volution,  7mm;  divergence 
of  apical  angle,  24°. 

In  many  particulars  this  species  is  closely  allied  to  Loxonema  cerithifor- 
mis  M.  andW.  (Geol.  Surv.  111.,  vol.  ii,  p  379,  pi.  xxxi,  figs.  13a-c),  and 
Chemniteia  subconstricta  De  Koninck  (Anm,  Foss.,  plate  Iviii,  figs.  17  a,  &). 
It  differs  from  each  in  having  less  convex  volutions,  and  the  surface  striae  at 
the  suture  are  not  gathered  in  short  crenulations.  The  cast  has  the  form 
of  the  volution  shown  in  both  Meek's  and  De  Koninck's  figures. 


FOSSILS  OF  THE  CAEBONIFEEOUS. 


259 


The  slope  of  the  spire  of  L.  bella  is  more  like  that  of  the  minute  Chem- 
nitzia  Icevigata  Deshayes  (Leth.  Rossica,  pi.  xlii,  figs.  6  a,  &)  of  the  Tertiary. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  the  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Genus  PLEUEOTOMAEIA  Defrance. 

Pleurotomaria  nodomarginata  McChesney. 
Plate  xviii,  fig.  15. 

Pleurotomaria  nodomarginata  McChesney,  1860.     Desc.  New  Species  of  Fossils,  p.  70. 
Trans.  Chicago  Acad.  Sci.,  1869,  vol.  i,  p.  47,  pi.  vii,  figs.  1  a-c. 

Notwithstanding-  that  Mr.  McChesney  gives  the  Hamilton  Group  as  the 
horizon  from  which  P.  nodomarginata  was  obtained,  the  identification  is  here 
made  with  a  shell  coming  from  the  Lower  Carboniferous  of  the  Eureka  Dis- 
trict. This  conclusion  is  arrived  at  only  after  the  most  careful  comparisons, 
which  appear  to  leave  very  little  if  any  doubt  of  the  specific  identity  of  the 
Nevada  and  Missouri  shells. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group,  east 
side  of  Secret-canon-road  Canon  on  east  slope  of  a  small  conical  hill,  Eu- 
reka District,  Nevada. 


Pleurotomaria  Nevadensis,  n.  sp. 
Plate  xxiv,  figs.  2,  2  a. 

Shell  turbinate;  spire  elevated,  height  and  width  subequal;  volutions 
five  or  six,  expanding  quite  regularly  to  within  a  half  of  a  volution  of  the 
aperture,  when  it  becomes  more  ventricose ;  body  volution  angulated, 
depressed  convex  above  and  rounded  below;  umbilicus  small.  Aperture 
broadly  oval  to  subcircular. 

Surface  marked  by  strong,  regular,  revolving  lines  above  and  below 
the  peripheral  band,  crossed  and  cancellated  by  finer  concentric  striae  that 
cut  into  the  revolving  lines  and  give  them  a  fine  nodose  appearance.  The 
concentric  strise  are  directed  a  little  backward  from  the  suture  to  the  band; 


260  PALEONTOLOGY  OF  THE  EUKEKA  DISTRICT. 

arching  backward  in  crossing  the  rather  narrow  surface  defined  by  the  sim- 
ple carina  above  and  below,  they  trend  forward  at  about  the  same  angle  to 
the  suture  as  they  do  above  from  the  band  to  the  suture. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Genus  MACROCHEILUS  Phillips. 

Macrocheilus,  sp.  f 
Plate  xxiv,  fig.  8. 

The  general  form  of  this  species  is  not  unlike  that  of  Macrocheilus 
Altonensis  Worthen  (Geol.  Snrv.  111.,  p.  593,  pi.  xxviii,  fig.  8)  of  the  Coal 
Measures  of  Illinois.  Owing  to  the  imperfect  preservation  of  the  aperture, 
it  is  impossible  to  make  a  satisfactory  specific  reference. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Genus  METOPTOMA  Phillips. 

Metoptoma  peroccidens,  u.  sp. 

Plate  xviii,  %.  16. 

Shell  depressed,  patelliform,  rounded  quadrangular  or  suboval  in  out- 
line, the  greater  and  less  diameters  being  26mm  and  20mm;  apex  subcentral, 
with  the  sides  sloping  away  uniformly  to  the  lateral  margins  and  not  quite 
as  rapidly  to  the  anterior  and  posterior  margins. 

Surface  marked  by  fine  concentric  lines  or  striae  of  growth  and  narrow 
radiating  lines  of  a  darker  color.  The  original  color  of  the  shell  is  par- 
tially preserved,  the  dark  radiating  lines  of  color  on  the  purplish-gray  sur- 
face giving  it  the  appearance  of  a  recent  Acmsea  (A.  testudinalis). 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  Group, 
Richmond  Mountain,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CAKBONIFEKOUS. 


261 


FIG.  4.  —  Outline 
figure  of  a  typi- 
cal shell,  X  3. 


Genus  AMPULLARIA  Lamarck. 

Ampullaria  ?  Powelli  Walcott. 
[mpullaria  f  Powelli  Walcott,  1883.     Science,  vol.  ii,  p.  808,  figs.  3,  3 a. 

Shell  subglobose;  umbilicus  small;  spire  depressed;  volutions  three  or 
four,  increasing  uniformly  in  size  until  the  last  one,  which  is  larger  in  pro- 
portion and  slightly  expanded  at  the  aperture;  suture  dis- 
tinct; aperture  oblong,  broad  ovate,  and  a  little  straightened 
on  the  inner  side,  entire;  peristome  continuous,  slightly 
reflexed. 

Surface  marked  by  fine  lines  of  growth.  Operculum 
concentric,  rather  thick,  and  of  a  calcareous  or  shelly  struct- 
ure; nucleus  subcentral. 

In  referring  this  species  to  the  genus  Ampullaria  we 
bear  in  mind  that  it  is  not  probable  that  a  genus  of  this 
character  has  continued  from  the  Middle  Paleozoic  to  the 
present  time;  on  the  other  hand,  when  we  consider  that  the 
shell  is  Ampullaria-like  in  character  and  associated  with  an  operculum  that 
is  almost  characteristic  of  the  genus,  that  the  genus  Pupa  is  known  from 
the  Middle  Carboniferous,  and  that  a  shell  not  to  be  distinguished  from 
the  recent  Physa  is  associated  with  Ampullaria  f  Powelli,  a  pulmonif- 
erous  shell  Zaptychius  Carbonaria  and  a  twig  of  a  coniferous  tree,  all  of 
which  are  evidences  of  a  near  land  area,  it  would  appear  that  a  reference 
to  Ampullaria,  as  the  genus  representing  the  group  to  which  the  species 
belongs  is  warranted  by  the  facts,  although  it  may  be  ultimately  referred  to 
a  new  genus  or  subgenus. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
on  the  western  slopes  of  New  York  and  Richmond  Mountains,  Eureka  Dis- 
trict, Nevada. 


FIG.    5.  —  Opercu- 
lum, X  3. 


PULMONIFERA. 

For  an  excellent  summary  of  what  was  known  of  the  Paleozoic  rep- 
resentatives of  this  subclass  up  to  the  month  of  November,  1880,  we  are 
indebted  to  Dr.  J.  W.  Dawson,  who  states  that  the  three  known  localities  of 
their  occurrence  are  on  the  American  continent,  and  that  six  species  were 


262  PALEONTOLOGY  OP  THE  EUREKA  DISTRICT. 

described  from  them,  namely:  Pupa  vetusta,  P.  Bigsbyi  Dawson,  Zonites 
(Conulus)  prisons  Carpenter,  from  the  Coal  Measures  of  the  South  Joggins, 
Nova  Scotia;  Pupa  Vermillionensis,  Dawsonella  Meeld  Bradley,  from  the 
Upper  Coal  Measures  of  Vermillion  River,  Illinois,  and  Strophites  grandczva 
Dawson,  from,  the  Devonian  plant  beds  of  St.  John,  New  Brunswick  (Amer. 
Journ.  Sci.,  3d  ser.,  vol.  xx,  p.  403,  1880).  Subsequently  Prof.  R.  P.  Whit- 
field  gave  the  results  of  his  study  of 'Dawsonella  Meeki,  showing  that  it  was 
probably  an  operculate  shell,  and  he  also  described  Antliraco-pupa  Ohioensis 
from  the  higher  beds  of  the  Coal  Measures  at  Marietta,  Ohio  (Ibid.,  xxi, 
p.  125,  -881).  All  of  the  species  are  true  land  shells,  the  aquatic  division 
of  the  Pulmonifera  being  unrepresented  up  to  the  time  of  the  discovery  in 
Nevada  of  the  species  to  be  described.  The  geologic  horizon  at  which  the 
latter  occur  is  intermediate  in  position  to  the  Devonian  plant  beds  of  New 
Brunswick  and  the  localities  in  the  Coal  Measures  of  Nova  Scotia,  Illinois, 
and  Ohio. 

A  brief  notice  of  these  shells  was  published  in  Science,  vol.  ii,  p.  808, 
1883. 

Genus  PHYSA  Draparnaud. 

Physa  prisca  Walcott. 
Physa  prisca  Walcott,  1883.    Science,  vol.  ii,  p.  808,  fig.  2. 

Shell  small,  oblong,  sinistrally  spiral,  and  with  about  four  volutions, 
the  last  one  expanded,  ventricose,  with  the  short,  small  spire 
above  less  than  one-fourth  its  length ;  aperture  more  than  three- 
fourths  of  the  length  of  the  body  volution,  broadly  rounded 
anteriorly,  becoming  more  pointed  at  the  opposite  end;  outer 
lip  thin,  inner  lip  slightly  reflected  on  the  last  whorl. 

Surface  smooth  or  marked  by  fine  lines  of  growth. 

FIG.  6.— Outline 

The   shell  is  apparently  that  of  a  true   Physa,  although     ofaheii.xs. 
thicker  than  in  most  species  of  the  genus.     It  may  belong  to  a  subgeneric 
group,  but  of  this  we  have  little  evidence  in  the  specimens  before  us. 

The  largest  specimen  has  a  length  of  91™1,  and  the  smallest  of  4mm. 

Formation  and  localities. — Lower  portion  of  the  Carboniferous  Group, 
in  a  chocolate-colored  limestone,  on  the  western  slope  of  New  York  and 
Richmond  Mountains,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CARBONIFEROUS. 


263 


Genus  ZAPTYCHIUS,  n.  g. 

Shell  minute,  elongate;  aperture  large,  oblong,  nearly  vertical;  outer 
lip  thin,  columellar  lip  reflected,  plicated. 

Surface  of  shell  marked  by  slightly  oblique  longitudinal  strias. 

Type:  Zaptycliius  carlo  a  aria. 

Zaptychius  appears  to  have  its  nearest  living  ally  in  Auricula,  although 
differing  in  the  form  of  the  body  volution  and  spire  from  the  typical  forms 
of  that  genus  ;  the  presence  of  the  Auricula-like  aperture  and  elongate  shell, 
vertically  striated,  afford  the  basis  for  a  new  generic  description. 


Zaptychius  carbonaria  Walcott. 
Zaptycliius  carbonaria  Walcott,  1883.     Science,  vol.  ii,  p.  808,  fig.  1. 

Shell  small,  slender,  the  body  volution  having  a  length  of  about  6.5T 
and  a  greater  diameter  of  2.5min;  aperture  rather  large,  elon- 
gate, narrow  posteriorly  and  broadly  rounded  in  front;  col- 
umellar lip  thickened  anteriorly,  the  thickened  portion  curv- 
ing inward  opposite  the  umbilical  chink  to  form  a  rounded 
plication  or  ridge  on  the  lip,  which  is  reflected  back  on  the 
volution  and  marked  by  a  second  tooth-like  plication  pro- 
jecting a  short  distance  out  into  the  aperture  a  little  posterior 
to  the  first.  The  number  of  volutions  is  unknown. 

Surface  of  the  shell  marked  by  even,  equidistant,  nearly 
vertical  stria3  that  distinctly  define  the  interspaces  between 
them. 

The  form  of  the  spire  above  the  portion  of  the  volution 
preceding  the  body  volution  is  unknown,  although  from  the  type"Bpecimen,  xs. 
character  of  that  preserved  and  the  presence  of  a  trace  of  a  volution  3.5mm 
above  the  body  volution,  it  was  probably  more  or  less  slender  and  elongate. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  formation, 
in  a  chocolate-colored  limestone,  associated  with  Physa  prisca 
ria  f  Powelli,  Eureka  District,  Nevada. 


264  PALEONTOLOGY  OF  THE  EUEEKA  DISTEICT. 

PTEROPODA. 
Genus  CONULAKIA  Miller. 

Conularia  Missouriensis  Swallow  f 
i    Plate  xxiii,  fig.  4. 

Conularia  Missouriensis  Swallow,  1860.    Trans.  St.  Louis  Acad.  Sci.,  vol.  i,  p.  657. 

The  description  given  by  the  author  of  this  species  agrees  so  closely 
with  the  specimen  before  me  that  in  the  absence  of  the  type,  or  a  good 
illustration,  it  is  identified  with  it.  Both  the  Missouri  and  Nevada  speci- 
mens occur  in  the  lower  portion  of  the  Lower  Carboniferous  limestone. 

Formation  and  locality. — Lower  portion  of  the  Lower  Carboniferous 
limestone,  Mokomoke  Ridge,  White  Pine  Mining  District,  Nevada. 

Genus  HYOLITHES  Eichwald. 

Hyolithes  carbonaria,  n.  sp. 

Plate  xxiii,  fig.  3. 

Form  an  elongate  triangular  pyramid,  gradually  and  regularly  taper- 
ing to  an  acute  extremity;  angle  of  divergence  of  the  sides,  18°.  Trans- 
verse section  subovate,  slightly  convex  on  the  ventral  side,  the  lateral  mar- 
gins rounded,  and  the  dorsal  side  a  little  more  convex  than  the  opposite 
side.  Aperture  oblique,  the  ventral  side  being  a  little  prolonged.  Shell 
rather  thick.  Operculum  unknown. 

Surface  with  fine,  concentric,  radiating  or  longitudinal  striae. 

Dimensions:  length,    llmm;  diameter  at  aperture,  3.5mm  by  2mm. 

In  the  cast  a  longitudinal  groove  is  seen  on  the  ventral  face  near  each 
lateral  margin ;  it  extends  only  a  little  way  back  from  the  aperture. 

This  pretty  little  shell  has  the  form  of  Eyolitlies  aclis  Hall  (Pal.  N.  Y., 
vol  v,  pt.  2,  p.  197),  of  the  Devonian  of  New  York,  but  it  is  more  slender 
and  probably  a  much  smaller  species.  Also  compare  with  Hyolithes  novellus 
Barrande  (Syst.  Sil.  Boheme,  vol.  iii,  pi.  xv,  figs.  23,  24.) 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  cailon  directly  south  of  a  small  conical  hill  on  the  east  side  of 
Secret-canon-road  Canon,  Eureka  District,  Nevada. 


FOSSILS  OF  THE  CARBONIFEROUS. 


265 


CEPHALOPODA. 

Genus  ORTHOCERAS  Breynius. 

Orthoceras  Randolphensis  Worthen  T 

Plate  xviii,  tig.  1?. 

Orthoceras  annulato-costatum  Meek  &  Worthen,  1861.  Proc.  Acad.  Nat.  Sci.  Philad., 
vol.  xiii,  p.  147.  Ibid.,  1866.  Geol.  Illinois,  vol.  ii,  p.  304,  pi.  xxiv,  figs.  3a-b. 
(Not  Orthoceras  annulato-costatum  Boll,  1857.) 

Orthoceras  Randolphensis  Worthen,  1882.  Bull.  111.  State  Mus.  Nat.  Hist.,  No.  1,  p.  38. 
By  error  in  the  Bulletin  the  original  reference  of  this  species  is  given  as 
Orthoceras  annulo-costatum  M.  &  W.,  1862,  Geol.  Surv.  111.,  vol.  vi,  instead 
of  as  above. 

With  the  means  of  comparison  at  hand  the  fragmentary  remains  of  this 
form  from  Nevada  appear  to  be  identical  with  those  from  the  Chester  lime- 
stone of  the  Lower  Carboniferous  formation  of  the  State  of  Illinois.  The 
most  marked  difference  between  them  is  the  greater  obliquity  of  the  annu- 
lations  in  the  Nevada  specimens,  but  this  may  be  owing  in  a  measure  to 
the  crushing  of  the  tube,  which  is  compressed  very  much  in  all  the  examples 
collected. 

Formation  and  locality. — Lower  portion  of  the  Carboniferous  limestone, 
on  the  eastern  slope  of  a  small  conical  hill  on  the  east  side  of  Secret-canon- 
road  Canon,  Eureka  District,  Nevada. 


Orthoceras  Eurekensis,  n.  sp. 
Plate  xxiii,  figs.  2,  2  a. 

Shell  slightly  curved.  Transverse  section  broadly  oval;  the  dorso- 
ventral  diameter  the  shorter,  having  a  ratio  of  7  to  8  with  the  lateral  diam- 
eter. Tube  gradually  and  regularly  enlarging.  Chamber  of  habitation 
unknown.  Air-chambers  have  a  depth  of  4mm  where  the  dorso- ventral 
diameter  of  the  tube  is  14mm.  Septa  thin,  smooth,  moderately  concave. 
The  suture  has  a  broad  retral  curve  over  the  dorso-ventral  sides  of  the  tube, 
extending  forward  over  both  the  lateral  faces. 

Siphuncle  small,  slightly  eccentric,  and  nearer  the  dorsal  face  of  the 
septum ;  a  narrow,  flat  areola  surrounds  it  in  the  one  section  exposed  to 


286  PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 

view.  The  character  of  the  siphuncle  in  its  passage  between  the  septa  has 
not  been  observed. 

The  test  is  rather  strong,  and  is  vertically  striated  on  the  interior  as 
shown- in  the  cast,  the  strise  being  exceedingly  fine.  The  exterior  surface 
has  been  so  injured  by  the  mineralization  of  the  test,  that  its  characters  are 
not  determinable. 

A  slight  carina  is  preserved  on  the  cast  of  the  dorsal  surface.  It  does 
not  appear  to  have  any  connection  with  the  siphuncle  or  areola  surround- 
ing it. 

Orthoceras  clinocameratum  Wiuchell  (Amer.  Jour.  Sci.,  vol.  xxxiii,  p.  356, 
1862)  is  the  only  American  species  that  appears  to  correspond  to  this. 
With  the  description  to  decide  from,  it  does  not  appear  that  the  Michigan 
and  Nevada  shells  belong  to  one  species. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
canon-road  Canon,  Eureka  District,  Nevada. 


Orthoceras,  sp.  f 

A  small  species,  with  fine  vertical  annulations,  is  associated  with  0. 
Eurekensis.  It  appears  to  be  slightly  curved,  and  to  have  its  cone  enlarg- 
ing gradually  and  uniformly. 


PCECILOPODA. 

Genus  GRIFFITHIDES  Portlock. 

Griffithides  Portlocki  M.  &  W. 

Plate  xxiv,  figs.  4,  4fl,  6. 

Phillipsia  (Griffithides)  Portlocki  Meek  &  Worth  en,  1865.    Proc.  Acad.  Nat.  Sci.  Philad., 
vol.  xvii,  p.  268.    Ibid.,  1873.     Geol.  Surv.  Illinois,  vol.  v,  p.  625,  pi.  xix, 
.       fig-  6. 

The  detailed  and  elaborate  description  given  of  this  species  by  its 
authors  provides  the  means  for  a  close  comparison  between  it  and  the  Ne- 
vada specimens. 


FOSSILS  OF  THE  CABBONIFEKOUS. 


267 


The  most  striking  difference  is  the  greater  strength  of  the  postero-lateral 
spine  of  the  free  cheek  in  the  Nevada  form.  This,  however,  is  scarcely  a 
specific  variation,  and  the  other  variations  are  not  of  specific  value. 

Judging  from  the  external  features  of  the  head,  this  species  may  be  re- 
ferred to  the  genus  Griffithides.  In  the  cast  traces  of  two  anterior  pairs  of 
glabellar  furrows  appear,  but  these  are  not  seen  on  the  outer  surface  of  the 
shell.  Again,  the  form  of  the  glabella  is  that  of  the  typical  forms  of 
Griffithides. 

Of  the  nineteen  species  referred  to  the  genus  Phillipsia,  from  American 
Paleozoic  strata,  I  do  not  know  of  one  that  would  not  admit  of  question. 
Eight  are  founded  on  specimens  of  the  pygidiuin  alone,  and  the  generic 
reference  is  consequently  questionable.  One  species,  Phillipsia  Lodiensis 
Meek  (Pal.  Ohio,  vol.  ii,  p.  323,  plate  xviii,  fig.  3),  is,  as  suggested  by  Mr. 
Meek,  referable  to  the  genus  Proetus  or  a  subgenus  of  Proetus,  and  in  this 
same  list  may  be  included  the  two  Devonian  species  (ante  p.  211  and  Pal. 
N.  Y.,  Illustrations  of  Devonian  Fossils,  plate  xxi,  fig.  29,  P.  Icevis).  Of 
the  species  left,  none  appear  to  possess  the  typical  features  of  Phillipsia, 
but  on  the  contrary  are  more  nearly  allied  to  Griffithides. 

Formation  and  locality. — Lower  portion  of  Lower  Carboniferous  lime- 
stone, in  canon  directly  south  of  a  small  conical  hill  on  east  side  of  Secret- 
cafion-road  Canon,  Eureka  District,  Nevada. 


268 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


SYSTEMATIC  LIST  OF  FOSSILS  OF  EACH  GEOLOGIC  FORMATION. 

CAMBRIAN. 
PROSPECT  MOUNTAIN  GROUP. 


Genera  and  species 

Eureka. 

9 

a 
K 

1 

Remarks. 

Page. 

PORIFERA. 

X 

Type  from  the  Cambrian  of  Wales  

11 

ep  1                

x 

BRACHIOPODA. 

X 

Fragment  

XX 

Types  from  Eureka  and  White  Pine  Districts  Nevada 

12 

?  minuta  H.  &"W  

XX 

x 

Type  from  the  Eureka  District  

13 

XX 

Type  from  Schell  Creek  Range  Kevada 

13 

Obolella  discoidea  H.  &  W         

XX 

Type  from  Eureka  District  

14 

sp.  ?  

X 

Like  0.  pretiosa  Billings  

Acrothele  ?  dichotoma  n.  sp.  ?  

x 

14 

XX 

Type  from  the  Calciferous  formation  of  Newfoundland 

17 

X 

19 

sculptilis  Meek  

X 

Type  from  Gallatin  River,  Montana  

20 

Whitfieldi  n  sp  

x 

18 

Leptsena  Melita  II.  &  "W  

XX 

Type  from  Eureka  District  

22 

x 

• 

22 

gp.  I  

X 

x 

PTEROPODA. 
Stenotheca  elongata,  n.  sp  

X 

23 

Hyolithes  primordialis  Hal]  (sp.)  

x 

Type  from  Potsdam  sandstone  of  Wisconsin  

23 

Scenella  ?  conula,n.  sp.....  

x 

15 

PffiCILOPODA. 
AgTinstpa  bidens  TW  fifth    

XX 

x 

26 

communis  H.  &  W  

XX 

x 

Type  from  White  Pine  District,  Nevada  

27 

Neon  H.  &  W  

XX 

Type  from  Eureka  District 

27 

prolongus  H.  &  W  

x 

Type  from  Eureka  District  

28 

Richmondensis,  n.  sp 

x 

24 

seclusus,  n.  sp  

x 

25 

Olenellus  Gilbert!  Meek  

x 

Type  from  Piocho,  Nevada 

29 

Howelli  Meek... 

x 

Type  from  Pioche  Nevada 

30 

Iddingsi,  n.  sp  

x 

28 

Dicellocephalus  ?  angustifrons,  n.  sp  

x 

42 

bilobatus  H.  &  "W  .     . 

x 

Type  from  Eureka  District 

40 

?  expansus,  n.  sp  

x 

45 

flabellifer  H.  &  "W  

L. 

GeoL  Expl.  Fortieth  Parallel,  vol.  iv,  p.  227  

lole,  n.  sp....  

x 

43 

Marica,  n.  sp  

x 

44 

nasutas,  n.  sp  

x 

40 

Osceola  Hall  

x 

Type  from  the  Potsdam  sandstone  of  Wisconsin 

40 

?  quadriceps  H.&  W.. 

x 

Type  from  Ute  Peak,  Wahsatch  Range,  Utah  

45 

Richmondensis.  n.  so.  . 

X 

41 

SYSTEMATIC  LIST. 


269 


CAMBRIAN— Continued. 


Genera  and  species. 

Eureka. 

1 

1 

Remarks. 

Page. 

Ptychoparia  (?)  angulatns  H.  &  "W  

x 

Geol.  Expl.  Fortieth  Parallel,  vol.  iv,  p.  220  

Any  tus  H.  &  W  

X 

Type  from  Schell  Creek,  Nevada  

56 

(S.  )  breviceps,  11.  sp  

X 

49 

granulosus  H.  &  W  

XX 

Type  from  Eureka  District  ...  . 

57 

Haguei  H.  &  W.  (sp.)  

XX 

Typo  from  the  White  Pine  District,  Nevada 

57 

X 

54 

(?)  Liunarsfoni,  n.  sp  

x 

47 

mnculosus  H.  &  W.  (sp.)  .. 

XX 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  215  

nitidua  H.  &  W.  (sp.  )  

x 

TypA  from  'Enrfltft  Diatrict  .... 

57 

occidentalis,  n.  sp    

x 

51 

Oweni  M.  &  H.  (sp.)  

XX 

Type  from  Big  Horn  Mountains,  Montana  

55 

(?)  pernasutus,  u.  sp  

x 

49 

(?)  Prospectcnsis,  n.  sp.  .  .  . 

x 

46 

(?)  similis,  n.  sp  

x 

52 

(?)similis  var.  robnstns,  n. 

x 

53 

var. 
unisulcatus  II.  &  \V    .. 

XX 

Type  from  Eureka  District  

58 

(Enloina  ?)  aflinis  n.  sp 

XX 

54 

x 

51 

(P.)4aticeps  H.  &  W 

x 

Type  from  White  Pine  District,  Nevada  

59 

x 

58 

sp  ?       .  .           ... 

x 

x 

59 

Ptycliaspis  minuta  Whitfleld  

x 

Type  from  the  Potsdam  sandstone  of  Wisconsin.  

60 

L. 

Geol.  Expl.  Fortieth  Par.  ,  voL  iv,  p.  223  

x 

L. 

Type  from  the  White  Pine  District,  Nevada  t    . 

61 

x 

61 

XX 

62 

x 

63 

x 

63 

x 

16  The  species  from  the  White  Pine  District  occur  at  the  base  of  the  Pogonip  Group  and  are  doubtfully  referred  to 
the  Cambrian.  « 


270 


PALEONTOLOGY  OF  THE  EUEEKA  DISTBICT. 


LOWER  SILURIAN. 


POGONIP  GROUP. 


[The  letter  C  in  the  first  column  denotes  that  the  species  also  occurs  in  the  Cambrian.] 


Genera  and  species. 

Eureka,  Lower. 

Eureka,  Upper. 

WliitoPiuo,  Lower 
and  Upper. 

Remarks. 

Page. 

RHIZOPODA. 

X 

07 

X 

66 

X 

U. 

85 

HYDROZOA. 

X 

Like  G.  bifidns  Hall  

ACTINOZOA. 

x 

« 

POLTZOA. 

X 

BRACHIOPODA. 
Lirgulepis  Maera  H  &.W  

C. 

Types  from  the  Eureka  and  White  Pine  Districts, 

U 

!  miuuta  H  &  "W  

C. 

Nevada. 

Type  from  Eureka  District 

13 

C. 

Type  from  the  Scholl  Creek  Range,  Nevada 

13 

L. 

x 

67 

discoidea  n.  Jt  W  

C. 

L. 

Tvpe  from  Eureka  District  

14 

Acrotrota  gemma  1T  Billings  

C. 

L. 

Type  from  Calciferous  Formation  of  Newfoundland 

17 

x 

Like  A.  subconica  Kutorga  

x 

70 

C. 

Tvpe  from  Eureka  District    . 

°2 

Strophomena  Xemoa  H.  &  \V  

x 

L. 

Type  from  White  Fine  District,  Nevada  

71 

x 

73 

x 

74 

x 

U. 

Trenton  of  Wisconsin,  Chazy  of  Canada,  etc 

72 

PoiTonipcnsis  H.  &.  TV"  

x 

U. 

GeoL  ExpL  Fortieth  Par.,  vol.  iv  p.  232 

x 

U. 

Trenton  Group  species  of  New  York  Canada,  etc 

72 

tricenaria  Conrad  

X 

TT. 

Trenton  Group  species  of  New  York,  Canada,  etc 

74 

gp.  f      

x 

X 

U. 

x 

76 

Porambi  nites  oliscnrus  H.  &  W^  

Geol.  ExpL  Fortieth  Par.,  voL  iv,  p.  234 

x 

Oaleifpmii^  fftrm»tfon  of  Cftnadft* 

75 

LAMELLIBRANCHIATA. 
Tellinomya  contracts  Salterf     .      ...... 

x 

U. 

Trenton  Group  species  .. 

78 

x 

78 

X 

17. 

77 

X 

tr. 

78 

so.  ?  ... 

TT. 

17  Identified  by  Mr.  Meek  from  Malade  City,  Utah.    Hayden's  Report  for  1872,  p.  464. 


SYSTEMATIC  LIST. 


271 


SILURIAN— Continued. 


Genera  and  species. 

Eureka,  Lower. 

Enreka,  Upper. 

"White  Pine,  Lower 
and  Upper. 

Eemarks. 

I 
Page. 

GASTEROPODA. 
Bellerophon  (Bucania)  bidorsata  Hall  

U. 

Trenton  Group  species  in  Now  York  Canada,  etc 

ep.  ?  

X 

Like  B.  allegoricus  White 

Straparollns,  sp.  ?  

U. 

Raphistoma  Nasoni  Hall  (sp.)  

X 

Trenton  Group  of  Wisconsin 

79 

sp.  ?  

X 

Murchisonia  Milleri  Hall 

TJ 

sp.?  

X 

sp.  I  

U. 

Plenrotomaria  Lonensis,  n.  sp  

X 

TJ. 

80 

sp.  1  

X 

Holicotoma,  sp.  ?  

x 

81 

Maclurea  annulata,  n.  sp  

x 

U. 

81 

carinata,  n.  sp  

x 

82 

snbaunulata,  n.  sp  

x 

82 

sp.  I  .  . 

x 

83 

Mctoptorua  ?  analoga,  n.  sp...  

U. 

84 

U. 

83 

Cyrtolltes  sinuatua  H  &  W 

x 

Type  from  the  White  Pine  District  Nevada 

su 

PTEROPODA. 

x 

u. 

83 

Hyolithes  Vanuxemi  n.  sp    .... 

x 

85 

sp.  f  

u. 

CEPHALOPODA. 
Orthoceras  multicameratum  Hall 

x 

u. 

A  species  of  the  Lower  Trenton  in  New  York 

86 

4sp.?  ... 

TJ. 

86  87 

Endocer.18  (like  E.  tnultitubulalum) 

x 

Species  of  Lower  Trenton  in  New  York  State 

87 

x 

86 

CRUSTACEA. 
Leperditia  bivia  White  ... 

x 

Type  from  the  Schell  Creek  Range  Nevada 

88 

x 

88 

Beyrichia  sp.  I  

x 

88 

x 

88 

PCECILOPODA. 
Agnostus  communis  H.  &  W  ............. 

C. 

Type  from  White  Pine  District,  Nevada  

27 

x 

GeoL  Expl.  Fortieth  Par.,  voL  iv.  p.  231  

Dicelloceplial  us  incxpectans,  n.  sp  

x 

90 

final  is,  n.  sp....          .... 

x 

89 

x 

GeoL  Expl.  Fortieth  Par.,  voL  iv,  p.  226  

x 

91 

C. 

Type  from  Eureka  District 

57 

Haguei  H.  &  W.(sp.) 

C. 

Type  from-the  White  Pine  District  

57 

C. 

Geol.  Expl.  Fortieth  Par.,  vol.  iv  p.  215  

u. 

55 

C. 

58 

(Euloma  ?)  afl'mis.  n.  SD.  1  .  .  . 

n. 

L. 

... 

54 

272 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


LOWER  SILURIAN— Continued. 


Genera  and  species. 

Eureka,  Lower. 

Eureka,  Upper. 

White  Pine,  Lower 
and  Upper. 

Remarks. 

Page. 

C. 

62 

x 

92 

Pogoniponsis  H.  &  W   .. 

U. 

GeoL  ExpL  Fortieth  Par.,  vol.  iv,  p.  243  

x 

93 

?  tnberculatus  n.  sp     .  .     .  . 

x 

U. 

91 

fsp.f  

U. 

Cyphaspis  ?  brevimarginatus,  n.  sp  

x 

93 

Amphion  Nevadensis,  n.  sp  

X 

U. 

94 

sp.  1                     

x 

SB.  ?  

tr. 

Ceraurus  sp.  ?  

x 

95 

Symphysurus  ?  Goldfnssi,  n.  sp  

x 

95 

Barrandia  t  McCoy  i,  n  sp     

x 

96 

?  sp  .  .  . 

x 

96 

Ulsenurus  Eurekensis,  n.  sp    ...     .... 

x 

L. 

97 

Jllaenus  crassicauda  Wahlenborg  (sp.)  .  . 

u. 

"Very  abundant  in  Upper  Pogonip  

ap.  1                            

x 

Asaphus  Caribouensis,  n.  sp   

x 

98 

?  curiosus  Billings 

x 

Typo  fmiri  fhfl  Qnpl>pij  (rrppp  of  Canada  -  *  -  -  ....,- 

98 

3  8D.  }  .  . 

x 

SYSTEMATIC  LIST. 


273 


LONE   MOUNTAIN   SILURIAN. 


Genera  and  species. 

Lower  Silu- 
rian. 

Upper  Silu- 
rian. 

s 

Remarks. 

Page. 

ACTINOZOA. 
Streptelasma,  n.  sp  

X 

,sp.  ?  

X 

Zaphrentis  ?  sp.  ?  

X 

Halvsites  catenulatus  Linn  (sp.)  

X 

u. 

Montieulopora,  sp.  ?  

x 

ECHINODERMATA. 
Cvstid  

x 

Separate  plates       .  .. 

BEACHIOPODA. 
Leptsena  sericca  Sowerby  

X 

Orthis  

x 

Like  O  plicatella 

CEPHALOPODA. 
Orthoceras,  sp.  ?  

X 

Ovrtoceras,  sp.  ?  

X 

PO3CILOPODA. 
Ceraurus  

X 

X 

Trinucleus  concentricus  March      

x 

Illitnus  

Asaphns  platvcephalns  Stokes  

x 

18  C  D  W 


274 


PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 


DEVONIAN. 

ABBREVIATIONS. — Up.  Held.  =  Upper  Helderberg.     Ham.  =  Hamilton  Group.     Ch.  =  Chemung  Group  of  the  Devonian 
series  of  the  Geological  Survey  of  New  York.    H.  &  W.  =  Hall  &.  Whitfield,  Geol.  Expl.  Fortieth  Parallel,  vol.  iv,  1877. 


Genera  and  species. 

Lower. 

! 

White  Pine, 
Upper. 

Remarks. 

Page. 

PORIFERA. 

X 

99 

X 

99 

X 

x 

100 

ACTINOZOA. 

x 

101 

x 

100 

x 

Held.  Falls  of  Ohio. 

100 

x 

101 

X 

GeolTExpl.  Fortieth  Par.,  vol.  iv,  p.  25  

Rockfordensis  Hall  ?  



X 

X 

Type  from  Devonian  of  Iowa  
Up.  Held  of  New  York  and  Falls  of  Ohio 

102 

x 

Up.  Held,  of  New  York  and  Falls  of  Ohio 

10° 

sp.  i                         

x 

Up.  Held,  of  New  York  and  Falls  of  Ohio  

102 

x 

Up.  Held,  of  New  York  and  Falls  of  Ohio 

10° 

x 

Up  Held  of  New  York  and  Falls  of  Ohio 

103 

x 

x 

103 

Aulopora  serpens  Goldfuss  

x 

Ham.  of  Michigan  

103 

x 

Up.  Held,  of  New  York,  Canada  Falls  of  Ohio  etc 

104 

Davidson!  M.  Ed 

x 

Hamilton  of  Iowa  

104 

x 

Up.  Held,  of  New  York,  Falls  of  Ohio  etc 

104 

,  2  n.  sp     

x 

104 

sp.  1 

X 

105 

Accrvularia  pentegona  Goldfuss  

x 

X 

Identified  by  Meek,  from  White  Pine  Dist.  Nevada 

105 

Smithia  Hennaliii  LoiisduU'  (sp.)  

X 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  32  

Pacliyphvllum  Woodman!  White,  sp  

x 

Devonian  of  Iowa    

105 

Diphyphyllum  Simcoense  M.  Ed 

x 

x 

Up.  Held  of  New  York,  Falls  of  Ohio  etc 

105 

PtychophyUum  ?  iniundibulum  Meek 

X 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  28 

Cystiphvlluna  Americanum  M.  Ed 

x 

Up.  Held.  New  York   Falls  of  Ohio  etc.  •  Ham  of 

106 

.  2  n.  8D   .. 

x 

New  York,  etc. 

106 

POLTZOA. 
Fenestella,  2  sp.  ?  

x 

Thamniscus  ?  sp.  ?  

x 

BRACH1OPODA. 
Lingula  Alba-pinensis,  n.  sp  

X 

108 

Lsena  Hall  

x 

Ham.  Group  of  New  York  

106 

Ligea  Hall  

x 

Ham.  Group  of  New  York  

107 

Ligea,  var.  Nevadensis,  n.  var  

x 

107 

Lonensis,  n.  sp  

x 

108 

MelieHall  
Whitei,  n.  sp  

X 

x 



Pal.  N.  Y.,  vol.  iv,  p.  14  

109 

,  sp  ?  

x 

Discina  Lodensis  Hall  

x 

Ham.  of  New  York  

112 

minuta  Hall  ?  

x 

Ham.  of  New  York  .'  

112 

,  sp.  ?  .  .  . 

X 

112 

SYSTEMATIC  LIST. 


275 


DEVONIAN— Continued. 


Genera  and  species. 


Remarks. 


Page. 


Pholidops  bellula,  n.  sp 

quadrangularis,  n.  sp 

Orthis  impressa  Hall 

McFarlanei  Meek 

Tulliensis  Vanuxem 

Skenidium  Devonicum,  n.  sp 

Streptorhynchu i  Cheinuiigensis  Conrad 

(sp.) 

Chemungensis,  var.  Pan- 
dora Billings. 
Chemuugeusis,  var.,  per- 

versa  Ilall. 
Strophonu'narhoniboidalisWilckens  (sp.) 

Strophodonta  arcuata  Hall 

Calvini  Miller  

ranucf  II.  &.  W 

demissa  Conrad  (sp.) 


Ch.  of  New  York 

Type  from  Mackenzie  River,  British  America 
Ham.  of  New  York 


Up.  Held.,  Ham.,  and  Ch.  of  New  York. 


Up.  Held,  of  New  York  and  Canada 


Up.  Held,  and  Ham.  of  New  York. 


iuequiradiata  Hall 

Patcrsoni  Hall 

perplana  Conrad,  (sp.) 

punctulifera  Conrad  (sp.) 

Chonetes  deflecta  Hull 

filidtriata,  n.  sp 

liemisplu  rica  Hall 

macrostriata,  n.  sp , 

mncronata  Hall 

setigera  Hall  

,  sp.  ? 

Productus  (P.)  Hallanus,  n.  sp 

(P.)  hirsutifonne,  n.  sp 

(P.)  lacbrymosus  Conrad  (sp.) 
(P.)  lacbrymosus,  var.,  limns 

Conrad  (sp.) 

(P.)  lachrymosus,    var.,    stig- 
matns  Hall. 

(P.)  navicellus  Hall  

(P.)  Shumardianus  Hall 

(P.)  Sbumardianus,  var.,pyx- 
idatus  Hall. 

(P.)  speciosus  Hall 

(P.)  subaculeatus  Murch . . . 

(P.)  truncatus  Hall 

, sp.  ?  

Spirifera  Alba-pinensis  H.  &  W 

clisj  uncta  Sowerby 

Englemanni  Meek  ? 

Parryana  Hall  ? 

Pinonensis  Meek 

raricosta  Conrad,  (sp.) 

strigosns  Meek 

Spirifera  varicosa  Hall 

sp.  undt 


Up.  Held.,  New  York,  Falls  of  Ohio,  etc 

Devonian  of  Iowa 

Devoi'ian  of  Iowa 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  246, 1877 

Devonian  of  Iowa,   New  York,  etc.;   Mackenzie 
River,  B.  A. 

Up.  Held,  of  New  York 

Up.  Held,  of  New  York 

Throughout  the  Devonian  of  New  York 

Throughout  the  Devonian  of  New  York 

Ham.  of  New  York  . . 


Up.  Held,  of  New  York  . 


Up.  Held,  of  New  York,  etc. ;  Great  Bear  Lake,  B.  A 
Ham.  of  New  York,  etc 


Devonian  of  Iowa 


Ch.  of  New  York 


Ch.  of  New  York 


Up.  Held,  and  Ham.  of  New  York. 

Devonian  of  Iowa 

Devonian  of  Iowa 


113 
114 
115 
114 
115 
116 
117 

117 
117 

118 
121 
122 


118 

120 
119 
120 
121 
124 
127 
123 
126 
124 
125 


130 
133 
132 
132 

132 

131 
129 
129 


133 

128 
131 


Ch.  of  New  York 

Up.  Held.  Falls  of  Ohio 

Ham.  of  New  York 

Of  the  type  of  P.  semireticulatus 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  255 

Ch.  of  New  York,  Mackensie  River,  B.  A.,  etc 134 

Type,  Eureka  and  White  Pine  Districts,  Nevada 138 

Devonian  of  Iowa  and  Canada 

Type,  .Pifion  Range,  Nevada 

Up.  Held,  of  New  York,  Falls  of  Ohio,  etc 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  43 

Up.  Held,  of  New  York,  Falls  of  Ohio,  etc 136 

...I      137 


137 
13* 
13r. 


276 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


DEVONIAN— Continued. 


Genera  and  species. 

Lower. 

Id 

o 

ft 

I 

"White  Pine, 
Upper. 

Remarks. 

Page. 

(M.)  glabra,  var.,  Nevadensis, 
n.  var. 

x 

139 

141 
143 
218 

X 
X 

X 

• 
Up  Held  of  New  York  and  Canada  

X 
X 
X 

146 
147 
147 
151 
220 
148 

x 

x 

Up  Held  and  Ham.  of  New  York         

x 

X 
X 

Athyris  Angelica  Hall  



X 

Ch.  of  New  York  

X 

x 

148 
148 
150 
150 
153 
155 
157 
152 
155 
152 

Up  Held  of  New  York 

x 

X 
X 

X 
X 
X 

X 
•  

X 
X 

Devonian  of  America,  Europe,  etc  

Type  from  Mackenzie  River,  B.  A  

Geol  Expl.  Foitii'th  Par.,  vol.  iv  p  247 

x 

x 

Devonian  of  Ohio  New  York  and  England 

X 

x 

\s 

Genesee  Slate  of  New  York 

Tethys  Billings 

x 

Up.  Held,  of  Canada  and  Falls  of  Ohio 

152 
159 
157 
158 

(L  )  Laura  Billings  

X 

x 

Ham.  of  Canada  and  New  York  

X 



Chemuiig  of  New  York  

X 

x 

Not  unlike  L.  acutiplicata  Hall 

159 
161 

x 

x 

X   * 

X 

163 
163 

x 

x 

LAMELLIBRANCHIATA. 

X 

x 

Geol.  Expl  Fortieth  Par   vol.  iv  p  93 

X 

x 

165 
165 
166 
166 
167 
167 
168 
168 

x 

x 

Leiopteria  Rafinesqnii  Hall  

x 

Ham.  Group  of  New  York 

x 

Limoptera  saraienticia,  n.  sp  

x 

Mvtilai'ca  dubia.  n.  sp    

x 

Chemungensis  Conrad  (sp.)  .  .  . 

X 



Chemung  Group  of  New  York  

sp.  ?  

x 

(Plethomytilus)  oviformia  Con- 
rad (sp.). 
Modiomorplia  altiforme,  n.  sp  

X 

x 

Ham.  Group  of  New  York 

169 

169 
170 

oblonga,  n.  sp  

X 

SYSTEMATIC  LIST. 


277 


DEVONIAN— Continued. 


Genera  and  species. 


Mocliomorpha  ohtusa,  n.  sp 

Goniophora  perangulata  Hall 

Palreoneilo,  sp.  ? 

Nucula  Rescuensis,  n.  sp 

,  sp.? 

Nuculites  triangulus  H.  &  W 

Bystactella  insularis,  n.  sp 

Megambonia  occidualis,  n.  sp 

Xyassa  parva,  n.  sp 

Grammysia  minor,  n.  sp 

Edmondia  Pinonensis  Meek 

Sauguinolites  ?  Combensis,  n.  sp 

'. linu-ilis,  n.  sp 

rigidus  White  &Whitfleld 
(sp.). 

?  Sanduskyonsis  Meek 

vi-nti  icosus  White  &  Whit- 
field  (sp.). 

Conocardiuin  Nevadeusis,  u.  sp 

.  sp  

Lunulicardiuui  li-igosuin  Meek  (sp.) 

Paracyclas  occidentals 

peroccidens  H.  &  W 

Posidonomya  Devonica,  u.  ep 

he  vis,  n.  sp 

Microdon  (C.)  macrostriatus,  n.  sp 

Cardiomorpba  Missourieusis  Swallow  . . . 

Anadoutopsis  aniygdaluifonnis,  n.  sp 

Schizodus  (Cytherodon)  orbicularis,  n.  sp. 
Cypricardinia  indent  a  Conrad,  (sp.) 

GASTEROPODA. 

Platy ceras  carinatum,  Hall 

conicurn  Hall... 


Conradi,  n.  sp 

dentalium  Hall 

nodosum  Conrad 

thetifonne,  n.  sp 

Thetis  Hall 

undulatum,  n.  sp 

Platy  ostoma  lincatum  Conrad 

sp.? 

Ecculioiuphalus  Devouicus,  n.  sp. 

Euomphalus  Eurekensis,  n.  sp 

(P.)laxus  Hall 

sp.? 


Straparollus  Newarkensis,  n.  sp. 

Pleurotomaria,  sp.  ? 

Platyschisma?  ambiguum,  n.  sp. 

?McCoyi,  n.  sp 

sp.? 


X 
X 

X          X 
X 


M. 


H. 
M. 


.9  . 

P4g 

•88 


Remarks. 


Schoharie  Grit  of  New  York. 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  248 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  46 


Chemung  of  New  York,  Burlington  Sandstone  of 

Iowa. 

Upper  Held,  of  Ohio 

Chemung  of  New  York,  Burlington  Sandstone  of 

Iowa. 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  92  . 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  248 . 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  277. 


"Upper  Held,  of  New  York  and  the  Falls  of  the  Ohio. 


Up.  Held,  and  Ham.  of  New  York 

Up.  Held,  and  Ham.  of  New  York,  and  Up.  Held. 
Falls  of  the  Ohio. 


Up.  Held,  of  Niew  York. 
Up.  Held,  of  New  York . 


Up.  Held,  and  Ham.  of  New  York. 

Up.  Helc^.  and  Ham.  of  New  York,  Canada,  etc. 


Page. 


171 
171 


172 
172 


172 
17S 
173- 
174 


Upper  Held,  and  Hani,  of  New  York . 


175 
175 
176 

176 
177 

177 


178 

179 

178 
180 

180 
181 
182 


182 
182 

182 
182 
183 
184 
182 
184 
185 

187 
185 
186 


187  - 


188 
188 


278 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


DEVONIAN— Continued. 


Genera  and  species. 

Lower. 

si 

p< 
p. 

p 

White  Pine, 
Upper. 

Remarks. 

Page. 

X 

189 

X 

- 

191 

X 

190 

x 

190 

'  subattenuatum  Hall  

X 

Up.  Held,  of  New  York  

191 

(2  sp  ?)                  

x 

19° 

gp  i                           ,        

x 

x 

193 

Leda  Hall                   

M. 

Ham  of  New  York 

194 

Lyra  Hall      

M. 

Ham.  of  N  ew  York  

194 

Mara  Hall  
Neleus  H.  &.  W  

x 

X 

x 

Ch.  of  New  York  
Geol.  Expl.  Fortieth  Par.  vol.  iv  p  250 

194 

Pelops  Hall             

M. 

Up  Held  of  New  York 

194 

X 

193 

X 

195 

x 

gpj                            

x 

SB   ? 

x 

Metoptoma  ?  Devonica,  n.  sp  

x 

195 

PTEROPODA. 

x 

Ham.  of  New  York  and  Canada                .... 

197 

bellulus  Hall  ?            

x 

197 

gracilistriatus  Hall  

X 

196 

X 

Up  Hold  of  New  York 

197 

Styliola  fissurella  Hall      

X 

x 

197 

x 

197 

X 

198 

x 

199 

Hvolithes  (like  H  Aclis  Hall)  

x 

199 

CEPHALOPODA. 
Orthoceras  (5  sp.  ?)     

X 

200 

x 

209 

x 

Geol  Expl  Fortieth  Par   vol.  iv  p  278 

X 

203 

Goniatites  desideratus,  n.  sp  

X 

203 

Kin"i  H  &  W 

x 

Geol  Expl  Fortieth  Par   voL  iv  p  '79 

gp?                            

X 

Like  (G  discoideus  Hall) 

CRUSTACEA. 

x 

204 

x 

206 

PCECILOPODA. 

x 

Up.  Held,  and  Ham.  of  New  York  Canada  etc 

207 

Dalnianit  i  js  Meeki  n.  sp  .... 

x 

208 

sp.  1               

x 

210 

M. 

Ham  of  New  York 

210 

marginalia  Conrad  (sp.)  

x 

Up.  Held,  of  New  York  

210 

8D.  ?.  .. 

x 

Phillipsia  coronata  Hall  ?  

M. 

Ham.  of  New  York  ...        

211 

SYSTEMATIC  LIST. 


279 


CARBONIFEROUS. 


Genera  and  species. 


Kemarka. 


Page. 


EHIZOPODA. 

Fusilina  cylindrica  Fischer  . 
robusta  Meek 


PORIFERA. 

Stromatopora,  sp.  ? 

ACTINOZOA. 

Zaphrentis,  sp.  ? 

Syringopora  umltattenuata '? 

Chaetetes  3  sp.  ? 

ECHINODERMATA. 

Archicocidaris  2  sp.  ? 

POLYZOA. 


Polypora,  sp.? 

sp.? 

Ptilodictya  (S.)  carbonarii  Meek?. 

(S.)  serrataMeek?  .... 

sp.? 

Fenestella  3  sp.  ? 

BRACHIOPODA. 


McChesney,  sp 


212 


Coal  Measures  of  Ohio. 
Coal  Measures  of  Ohio. 


Discina  connata,  n.  sp 

Newberryi  Hall 

uitida  Phillips  (sp.) 

sp.? 

Lingula  mytiloides  Sowerby  ? 

Chonetes  granulifera  Owen 

Verneuiliana  N.  &  P 

Prodnctus  oostatus  Sowerby 

elegans  McCoy 

longispinus  Sowerby 

longispinus,  var.  muricatusN. 
&P. 

Nebrascensis  Owen 

Prattenianus  Norwood 

punctatus  Martin  (sp.) 

semireticulatus  Martin  (sp.)  .. 

subaculeatus  Murch 

Strophomena  rhomboidalis  Linn.  (sp.). 
Streptorhynchus  crenistria  Phillips  (sp.). 

Orthis  Pecosi  Marcou 

resnpinata  Martin  (sp.) 

Spirifera  anncctans,  n.  sp 

camerata  Martin 

desiderata,  n.  sp 

LeidyiN.  &P 

neglecta  Hall 

Rockymoutana  Marcou 

striata  Martin 

trigonalis  Martin  (sp.) 

(Martinia)  setigera  Hall 


Hanerok  LibrsQ^ 


214 
213 
213 


U.  S.  Geol.  Surv.  Nebraska,  p.  170, 1872 

TJ.  S.  Geol.  Surv.  Nebraska,  p.  170, 1872 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  69, 1877. 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  78, 1877  . 


Expl.  &  Surv.  W.  100th  Merid.,  vol.  iv,  Pal.,  p.  116, 1875 

Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  72, 1877 

Expl.  &  Surv.  "W.  100th  Merid.,  vol.  iv,  Pal.,  p.  114, 1875 

Geol.  Expl  Fortieth  Par.,  vol.  iv,  p.  69, 1877 

Also  in  Devonian 


214 
118 


Expl.  &  Surv.  W.  100th  Merid.,  Pal.,  vol.  iv,  p.  125, 1875 
Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  265, 1877 


216 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  91, 1877. 


217 
216 
217 


Expl.  &  Surv.  "W.  100th  Merid.,  vol.  iv,  Pal.,  p.  134, 1875. 
Geol.  Expl.  Fortieth  Par. ,  vol.  iv,  p.  269, 1877 


215 


Geol.  Expl.  Fortieth  Par.,  vol.  iv,  p.  270, 1877. 


280 


PALEONTOLOGY  OF  THE  EUREKA  DISTRICT. 


CARBONIFEROUS— Continued. 


Genera  and  species. 

Lower. 

i 
1 

Remarks. 

Page. 

Sjiingothyris  cuspidatus  Martin  (sp.)... 
Spiriferina  cristata  Schlotheim  (sp.)  

X 

X 
X 
X 

x 

X 
X 

Davidson's  Monograph  Carb.  Brachiopoda  

219 
218 
220 

Also  in  Devonian  

Geol  Expl.  Fortieth  Par   vol.  iv,  p.  82  1877  

222 

X 
X 
X 

x 

X 

223 
223 

sp  $    

Leiorh  ynchus-like  

x 

224 

X 

ExpL  &  Surv  "W  100th  Merid   voL  iv  Pal   p  144  1875 

hastata  Sowerby  

x 

224 

229 
227 

220 
227 
228 
230 
230 
231 
232 
233 
234 
234 
235 
236 
235 
237 
237 

239 
239 
240 
240 
241 
241 
242 
243 
243 

LAMELLIBRANCHIATA. 

x 

Eurekensis,  n.  sp  

x 

Haguei  n.  sp  

x 

percccidens,  n.  sp  

x 

Pintoensis,  11.  sp  

x 

gap  '      

x 

x 

x 

. 

Pterinopecten  Hoosacensis,  n.  sp  

x 

Spio  n.  sp  

X 

Ptvchopteria  protoforiuis,  n.  sp  

X 

X 

x 

x 

Nemesis  n.  sp  

x 

x 

Modiola  ?  Nevadensis,  n.  sp  

x 

Modiomorpba  ambigua,  n.  sp  

x 

?  desiderata,  n.  sp  

X 

x 

?  Piutoensis,  n.  sp  

x 

levatiforme,  n.  sp  

x 

x 

Macrodon  Hamiltonae  Hall  

x 

Ham.  group  of  New  York  

ti'imcatus  n.  sp  

x 

tenuistriatus  Meek  &  Worthen  . 
Grammysia  arcuata  Conrad,  (sp.)  

x 

X 

Geol.  111.,  vol.  v,  p.  576,  1873  

Ham.  Grcup  of  New  York  

245 

244 
246 
24:> 
246 
247 
249 
247 
248 
248 
24i» 
250 

Hannibalensis  Shnmard  (sp.) 
Edmiindia  ?  circularis,  n.  sp  

X 

x 

Medon,  11.  sp  

x 

Pleurophorus  Meeki,  n.  sp  

x 

San°"iiuolites  .35olus  Hall  .   .  . 

X 
X 

x 

.... 

Waverly  of  Ohio            

i  Na;nia,  n.  sp  

Salteri,  11.  sp  

x 

x 

striata,  n.  sp  

x 

Microdon  (Cvpricardella)  connatus,  n.  SB. 

X 

SYSTEMATIC  LIST. 


281 


CARBONIFEROUS— Continued. 


Genera  and  species. 

Lower. 

1 

p 

Remarks. 

Page. 

Cardiola?  fllicostata,  n.  sp  

X 

251 

Schizodus  cuneatus  Meek  

x 

Coal  Measures  of  Ohio 

252 

curtiforme,  n.  sp  

x 

253 

deparcus  

X 

252 

Pintoensis,  n.  sp  

X 

253 

GASTEROPODA. 
Platyceras  occidens,  n.  sp  

X 

254 

Piso,  n.  sp  

x 

254 

Platyostoma  inornatuni,  n.  sp  

x 

255 

Euompbalus  (S.)  subrugosus  M.  &  W  

x 

255 

Loxonerua  bella,  n.  sp  

x 

258 

Macioclieilus,  sp.  ?  

x 

260 

Pleurotomaria  Nevadensis  

x 

259 

nodumarginata  McChesney 

x 

259 

sp.  ?  

x 

sp.  ?  

x 

Naticopsis,  sp.  ?  

x 

Not  unlike  N.  rana  M.  &  W  

Bellerophon  majuscula,  n.  sp  

x 

256 

tevtilis  Hall  .'. 

x 

257 

sp.  ?  

x 

sp.  ?  

x 

Like  B  snblsevis  Hall 

Metoptoma  peroccidens,  n.  sp  

x 

260 

Ainpullaria  ?  Powelli,  n.  sp  

x 

261 

PULMONIFEKA. 

Zaptychius  Carbonaria,  n.  sp  

x 

263 

Physa  prisca,  n.  sp    

x 

262 

PTEROPODA. 
Connlaria  Missouriensis  Shumard  

x 

264 

Hyolithes  Carbonaria,  n.  sp  

x 

264 

Dentalium  (like  D.  Primarium)  Hall  

x 

CEPHALOPODA. 
Orthoceras  Enrekensis,  n.  sp  

x 

265 

Randolphensis  Worthen  

x 

265 

(2sp.?)  

x 

266 

Gomphoceras  sp  

x 

Nautilus  (like  N.  digonis  M.  &  W.)  ...... 

x 

CRUSTACEA. 
Leperditia,  sp.  ?  

x 

PCECILOPODA. 
Griffithides  Portlocki  M.  &  "W.  (sp.) 

x 

266 

PALEOZOIC  SECTION  IN  CENTRAL  NEVADA. 

The  geologic  portion  of  the  accompanying  section  is  taken  from  the 
"Abstract  of  Report  on  the  Geology  of  the  Eureka  District,  Nevada,  by 
Arnold  Hague,"  contained  in  the  Third  Annual  Report  of  the  Director  of 
the  United  States  Geological  Survey,  p.  253.  It  is  introduced  to  enable 
the  student  at  a  glance  to  locate  in  the  geologic  section  the  position  of  any 
portion  of  the  Paleozoic  fauna  described  in  the  preceding  list. 

All  of  the  Cambrian  fauna  is  included  under  the  head  of  "  Prospect 
Mountain  Group,"  in  the  systematic  list. 

The  Lower  Silurian  includes  the  fauna  of  the  Pogonip  limestone  and 
the  base  of  the  Lone  Mountain  limestone,  only  two  or  three  species  of  corals 
indicating  the  presence  of  an  Upper  Silurian  fauna. 

The  Devonian  limestones  are  highly  fossiliferous  throughout.  The 
fauna  is  best  preserved  within  500  feet  of  the  base  and  summit,  the  massive 
beds  of  the  central  portions  yielding  but  very  few  good  specimens. 

The  White  Pine  shales  in  the  Eureka  District  gave  but  two  identified 
species  and  fragments  of  ten  others  referred  to  genera.  In  the  White  Pine 
District  the  fauna  is  scattered  through  the  shale  and  embraces  fourteen 
named  species  and  eleven  referred  to  genera. 

The  large  fauna  of  the  Lower  Carboniferous  occurs  within  a  range  of 
500  feet  above  the  summit  of  the  Diamond  Peak  quartzite.  Only  24  of  the 
132  species  of  the  Carboniferous  fauna  occur  above  that  horizon,  and  of 
these  10  are  present  in  the  lower  beds. 

283 


284 


PALEONTOLOGY  OF  THE  EUEEKA  DISTRICT. 


Paleozoic  section  of  Nevada, 


CABBONIFBROUS,  9,300  feet. 

Upper  Carboniferous  

500 

Light-colored  blue  and  drab  limestones  

Weber  conglomerate  .  -  

2,000 

Coarse  and  fine  conglomerates;  layers  of  reddish  yellow  sandstone. 

3,800 

>* 

Heavy-bedded  dark  blue  and  gray  limestone,  with  intercalated  bands  of 
chert  ;  argillaceous  beds  near  the  base. 

Diamond  Peak  quartzite  

3,  000 

Massive  gray  and  brown  quartzite,  with  brown  and  green  shales  at  the 
summit.  The  quartzite  is  largely  a  fine  quartzitic  conglomerate  formed 
of  Rtnnll,  dark  jaspery  pebbles  and  light  quartz  pebbles  in  a  gravish 
matrix. 

DEVONIAN,  8,000  I'cct. 

2,000 

Black  argillaceous  shales,  more  or  less  arenaceous,  with  intercalations  of 
red,  and  reddish  brown  friable  sandstone,  changing  rapidly  with  the 
locality;  plant  impressions. 

Nevada  limestone  

6,000 

Lower  horizons  indistinctly  bedded,  saccharoidal  texture,  grav  color,  pac- 
ing up  into  strata  distinctly  bedded,  browu,  reddish-brown'  and  grav  in 
color,  frequently  finely  striped,  producing  a  variegated  appearance.  The 
tipper  horizons  are  massive,  well-bedded,  and  bluish-black  in  color; 
highly  fossilii'erouB. 

SlLUUlAN,  5,000  i'cct. 

Lone  Mountain  limestone  

1,  800 

Black,  gritty  beds  at  the  base,  passing  into  a  light  gray  siliceous  rock,  with 
all  traces  of  bedding  obliterated  ;  Trenton  fossils  at  the  base  ;  Halvsites 
in  the  lower  portion. 

Eureka  qnartzite  

500 

Compact  vitreous  i|uart/.ite,  white,  blue,  passing  into  reddish  tints  iic.sr  tin- 
base;  indistinct  bedding. 

2,700 

Interstratified  limestone,  argillites,  and  arenaceous  beds  at  the  base,  passing 
into  purer,  fine-grained  limestone  of  a  bluish  gray  color,  distinctly  bedded  ; 
highly  fossiliferous. 

C'AMBUIAN,  7,700. 

350 

Yellow  argillaceous  shale,  layers  ot  chert^iodules  throughout  the  bed,  but 
more  abundant  near  the  top. 

Hamburg  limestone  

1,200 

Dark  gray  and  granular  limestone  ;  surface  weathering,  rough  and  ragged  : 
only  slight  traces  of  bedding. 

Secret  Canon  shale  

l.fiOO 

Yellow  and  gray  argillaceous  shales,  passing  into  shaly  limestone;  near  the 
top,  iuterstratified  layers  of  shale  and  thinly  bedded  limestones. 

Prospect  fountain  liuie^t  ue.  .  . 

3,050 

Gray,  compact  limestone;  lighter  in  color  than  the  Hamburgh  limestone, 
traversed  with  thin  seams  of  calcite;  bedding  planes  very  imperfect. 

Prospect  Mountain  qnartzite  .  .  . 

1,500 

Bedded  brownish  white  quarfzites,  weathering  dark  brown;  ferruginous 
near  the  base  ;  intercalated  thin  layers  of  arenaceous  shales  ;  beds  whiter 
near  the  summit. 

NOTE. — Plane  of  unconformity  indicated  by  double  dividing  line. 


PALEOZOIC  SECTION. 
Vertical  range  of  genera. 


285 


Upper  Carboniferous  genera:    Fusilina,   Zaphrentis,   Polypora,   Ptylodictya,   Chaetetes,   Orthis,   Productus,  Spirifera, 
Spiriferina,  Retzia,  Athyris,  Terebratula,  Myalina,  Macrodon,  Pleurotomaria. 

Non-fossiliferons. 


Lower  Carboniferous  genera:  Fusilina,  Stromatopora,  Syringopora,  Polypora,  Ptilodictya,  Feoestelld,  Archasocidaris, 
Lingnla,  Discina,  Streptorhynchns,  Orthis,  Chonetes,  Productus,  Strophomena,  Spirifera,  Syringothyris,  Spiriferina, 
Atbyris,  Rynchonella,  Camarophoria,  Terebiatula,  Aviculopecten,  Streblopteria,  Crenipecten,  Pterinopecten,  Pteri- 
nea,  Leptoilesiua,  Ptychopteria,  Pinna,  Myaliua,  Modiola,  Modiomoipha,  Nucula,  Solenomya,  Macrodon,  Grammy- 
sia,  Edmoudia,  Pleurophorus,  Sanguinolites,  Microdon,  Cardiola,  Schizodus,  Platyceras,  Platyostoma,  Bellerophon, 
Euomphnlus,  Loxoncma,  Macroclioilus,  Pleurotomaria,  Naticopsis,  Metoptoma,  Hj'olithes,  Dentaliunif  Conularia,  Orth- 
oceras,  Gomphoceras,  Kautilus,  Leperditia,  Griffithides. 


Productus  and  Athyris  alone  observed  in  a  calcareous  stratum  near  the  base  of  the  conglomerate  beds,  not  over  200 
feet  above  the  White  Pine  shale. 


Fauna  mostly  in  central  and  upper  portion  :  Cyathophyllum,  Fenestella,  Lingula,  Discina,  Orthis,  Chonetes,  Productus, 
Spirifera,  Amboca'lia,  Reizia,  Atbyris,  Ehynchonplla,  Avicniopecten,  Modiomorpha,  Palaeoneilo,  Nnculites,  Cardio- 
morpha,  Lumilicaidium,  Cj'pricardi'uia,  Conocardium,  Hyolithes,  Pleurotomaria,  Goniatites,  Cyrtoceras,  Proetus. 

Upper  500  feet:  Stiomatopova,  Alveolites,  Cladopora,  Syringopora,  Cyathophyllum,  Pachyphyllum,  Lingula,  Diacina, 
Orthis,  Streptorhynchus,  Strophodonta,  Chonotps,  Productus,  Spirifeva,  Athyris,  Atrypa,  Khynchonella,  Cryptoiiella, 
Pterinea,  Leptodesma,  Mytilarca,  Nucula,  Nyas>sa.  Gnimmysia,  Sanguinolites,  Paracyclas,  Euomphalus,  Straparollus, 
Platyschismn,  Bulleroplion,  Naticopsis,  Styliola,  Coloolus,  Gomphoceras,  Proetns,  Phillipsia?. 

Lower  500  feet:  Pateomanon,  Astylospongia,  Stroniatojiora,  Favosites,  Thecia,  Syringopora,  Aulopora,  Cyathophyllum, 
Acervularia,  Dtpbyphyllum,  Cystiphylhun,  Lingula,  Discina,  Pholidops,  Orthis,  "Skenidinm,  Streptoihynchus,  Stropho- 
mena, Stropliodoiita,  Cbonetes,  Prod'lCtus,  Spirifera,  Trematospira,  Js  ucleospira,  Meristella,  Atrypn,  Khynchouella, 
Pentameru.s,  Ciyptoue'ln,  Glyptodesma,  Pterinea,  Actinopteria,  Lciopteiia,  Limoptera,  Mytilarca,  Plethomytilus,  Mo- 
di(>:i)orpha.  (ionio])bora,  Dyslactclin,  Mc'iainboiiia,  Nyassa,  Edmondia,  Sanguinohtes,  Conocardium,  Paracyclas,  Posid- 
onomya,  llicrodon,  Anadontopsis,  ScbizoduH,  Cypricaidinia,  Platyceras,  Platyostoma,  Ecculiomphalus,  Euomphalus, 
Callonrma,  Loxonema,  Belleropliou.  Metoptoma,  Tentaculites,  Styliola,  Hyolithes,  Orthoceras,  Cyrtoceras,  Goniatites, 
15cyrichia,  Leperditia,  Phacops,  Proetus,  Dalmanites. 

Upper  Silurian  hori/on  :  Znphreutis,  Halysites. 

Lower  bods:  Streptelasma,  Monticulopora,  Leptsena,  Orthis,  Orthoceras,  Cvrtoceras,  Ceraurus,  Trinucleus,  Dalmanites, 
s,  Asaphus. 


Non-fosBiliferont). 


Upper  portion:  Keceptaculites,  Monticulopora,  Ptilodictya,  Graptolithus,  Acrotreta,  Strophomena,  Streptorhynchns, 
Orthis,  Triplesia,  Modiolopsis,  Tellinomya,  Bellerophon,  Murchisonia,  Raphistoma,  Pleurotomaria,  Hellicotoma, 
Macluroa,  Cyrtolite*,  Coleopiion,  Hyolithes,  Orthoceras,  Endoceras,  Leperditia,  Beyrichia,  Amphion,  Ceraurus, 
Symphasurus,  Cyphaspis,  Proetus,  Ilhenus,  Bathyurus,  Asaphus. 

Lower  portion :  Liugulepis,  Lingula  ?,  Discina.  Obolella,  Acrotreta,  Schizambon,  Leptaena,  Strophomena,  Orthis,  Trip- 
lesia, Agnostus,  Dicellocephalus,  Ptychoparia,  Aiethusiua,  lllasnurus,  Asaphus. 

Lingulepis,  Kutorgina,  Obolella,  Acrotreta,  Agnostus,  Dicellocephalus,  Ptychoparia,  Ptychaspis,  Arethusina. 
Traces  of  fossils. 

Upper  beds:  Protospongia,  Lingulepis,  Lingula?,  Discina.  Acrothele,  Acrotreta,  Kurtorgina,  Hyolithes,  Agnostus, 
Dicellocephalus,  Ptychoparia,  Agraulos,  Chariocephalus,  Ogygia?. 


Upper  beds:  Lingulepis,  Obolella,  Stenotheca,  Agnostus,  Dicellocephalus,  Ptychoparia. 
Middle  beds:  Sccnella,  Agn6stus,  Dicellocephalus?,  Ptychoparia. 


Upper  shaly  beds :  Kutorgina,  Olenellus,  Ptychoparia,  Anomocare. 


INDEX 


[Figures  in  heavy-faced  type  indicate  the  page  on  which  the  description  is  given.] 


Page. 

ACEKVULARIA  pentagona 1O5 

A  on.  A  test  udinalis 260 

ACROTHELE .,, 14,  69 

?  dichotoma 14 

ACROTRETA 16,69 

attenuata 17 

gemma 3,16,17,18,20,71 

pyxidicula *    17 

subconica 17 

ACTIXOPTERA 166 

ACTIXOPTERIA 166 

Boydi 164,166 

A(  -TIXOZO  A 100 

AGXOSTUS 24 

bidens 3,17,26,27 

communis 3,  27 

Neon 3,27 

25 

28 

24 

25 

271 

AGRAULOS 55,61 

?  globosus 61 

Oweni 55 

sp.?  55 

ALLORISMA  Hannibalensis 244 

subcuneata,  var 225 

tenninalis 225 

ALVEOLITES  multilamellata 274 

Rockfordensis 1O2 

AMBOCCELIA  umbonata 5,276 

AMPHION 94 

Xevadensis 94 

sp.  ? 272 

AMPULLARIA 261 

?Powelli 8,261,263 


pnnceps 

prolongus 

Richrnondensis 

seclusus 

tumidosus ... 


Page. 

ANODONTOPSIS 180 

amygdateformis 18O 


ANOMITES  cuspidatus 

ANOMOCARE 

acuminatam 

?parvum 

ANTHRACO-PUPA  Ohioensis 
ARCH^EOCIDARIB 

Shuinardiana 

Wortheni 


219 

59 

50 

59 

262 

212 

-213 

212 

212 

62 

Americana 3, 62 


ARETHUSINA  . 


Konincki 

ARIONELLUS  ?  Oweni 

(Crepicephalus)  Oweni 
=  Ptychoparia  Oweni . . 

ASAPHUS . . . 


35 

55 

55 

55 

98 

Caribouensis 3,98 

?  curiosa 

platycephalus 


98 

272 
272 
99 
99 


ASTYLOSPONGI A 

Sp.  1 

ATHYRIB 148,222 

Angelica 148,169 

Clara 149 

Cora 148 

hirsuta 222 

Maia 141 

nasuta 149 

{polita 224 

Royssii 222,280 

sublamellosa 5,  222 

subtilita 280 

trinuclea 224 

sp.? 148,276 

287 


288 


INDEX. 


ATKYl'A 

comis 

concinna . 


Page. 

, 150 

159 

147 

desquamata 15O 

duplicata 155 

nasuta 148,149 

pngnns  


155 


radiaiis 220 

retioularis 4,150,151,195 

AULOPOKA  serpens 1O3 

AVICULA  Boydi 166 

—  Pseudomonotis  curta 225 

flabella 165 

AVICULOPECTEN 226 

affinis 25*9,231,232 

catactus 5,104,276 

Coreyanus 225 

Coxanus 238 

curto-cardinalis 225 

Eurekensis 227,228,229,231 

Hague! ." 226,227,229,231 

I  interlineatus 225 

McCoyi 225 

occidaneus 225 

occidental 225 

parvulus 225 

peroccidens 227,229,231 

Pintoensis 228 

Utahensis 225 

Weberensis  225 

s]>.?  23O 

(Pecten)  plicatus 228 

BAKEVELLIA  parva 225 

BARRANDIA 96 

TMcCoyi 3,71,96 

?sp 96 

BATHYURUS 91 

caudatus 93 

?  congeneris 92 

oblongus 92,93 

?serratus 92 

?  simillimu  s 93 

tuberculatus 91 

lap.? 272 

BELLEROPHON 192,256 

cancellat  us 257 

Combsi 193 

costatus 256 

crassus 256 

ellipticus 258 

Leda 194 

Lyra 194 


Page. 

BELLEROPHON— Continued. 

Msera 194 

maj  usculus 256,257 

Neleus 278 

Pelops 194 

perplexa 192,193,195 

sublaevis 256 

textilis 257,258 

(Bueania)  bidorsata 271 

BEYRICHIA 88,204 

regularis 

Wilkensiana 205 

sp.» 88 

(Primitia)  occidentalis 2O4 

(l^rimitia)  simplex 205 

(Primitia)  strangulata 205 

BHACHIOPODA 12,67,106,213 

CALLONEMA 189 

imitator  189 

occidental 1 89 

•CALYMENE  bufo  var.  rana 207 

jnarginalis 21 0 

CAMARELLA  calcifera 71,75 

CAMAROPHOUIA 156,224 

Cooperensis 224 

CAMBRIAN,  Fossils  of  the 11 

Number  of  genera  and  species  in 9 

CARBONIFEROUS 212 

Corals  not  illustrated 7 

Fossils  of  the 212 

Species  of  Upper  Devonian  commingling  with 

fauna  of  Lower  8 

X  u  rnber  of  genera  and  species  in 9 

C  ARDIOLA 251 

Ifllicostata 251 

trausversa 251 

CARDIOMORPHA  Missouriensis 5, 6, 225 

CEPHALOPODA 86, 200, 265 

CERAURUS 95 

?sp.  unfit •- 95,272 

CH.ETETES 279 

CHARIOCEPH  ALUS 61 

?tjnnifrons 61 

CHEMSITZIA  laevigata 259 

subconstricta 258 

CHEMUNG  GROUP  of  New  York,  Number  of  species 
representing  the 

CHOXETES 122 

acutiradiata 124 

arcuata 123 

coronata 128 

deflecta...  124 


INDEX. 


289 


Page. 

CHONETES— Continued. 

filistriata 137 

gibbosa 124 

granulifera 279 

hcmispherica 5, 133 

lat  icosta 124 

raacrostriata ]  36 

mucronata 134,125 

setigera  135 

Verneuiliana 279 

sp.? ...  .          275 

CLADOPORA  prolitica 274 

pulcbra 4, 1O3 

sp.  undt .T 1O3 

COLEOLUS    199 

laevis 199 

COLEOPRION 85 

?Bohemicum 200 

in  i  nu  t  a 85 

COXCHYI.IOLITES  anomites  trigonalis 215 

COXCHYOUTIII s  imomites  pugnns 155 

CONOCARDIUM 177 

Xevadensis 177 

COXOCEPHALITES  (Pterocephalus)  laticeps 59 

=  Ptycboparia  arenoaus 55 

CONOCORYPHE  coronatus 48 

exsnlans 48 

Matthewi 48 

Solvensis 48 

(Elyx)  laticeps  .'. 48 

(Ptychoparial  Gallatiuensis 55 

=  Ptyt'boparia  Gallatinensis 55 

COXULARIA 198,264 

Missouriensis  364 

sp.nndt 198 

CORALS,  Carboniferous,  not  illustrated 7 

Devonian,  not  illustrated 7 

Silurian,  not  illustrated 7 

CKENIFECTEN - 231 

crenulatus * 231 

Hallanns 331,232 

Leon 231 

TVinchelli 229,232 

46 
55 
56 
55 
57 
57 
57 
57 
58 


CREPICEPHALUS 

centralis 

(Loganellus)  anytus 

(Loganellus)  centralis 

(Loganellus)  granulosus  . 

(Loganellus)  Haguei 

(Loganellus)  nitidus 

(Loganellus)  simulator... 

(Loganellus)  unisulcatus . 

19   C   D   W 


CREPICEPHALUS — Continued. 

(Loganellus)  =  Ptychoparia  Montanensis 

—  Ptychoparia  centralis 

=  Ptychoparia  planus 


Page. 

56 
55 
5C 

CRUSTACEA £8,204 

CRYPTONELLA 103 

?  circula 163 

Pinonensis 1 63 

pin  n  i  rostra 1(54 

CTENODONTA  contracta 76 

CYATHOPHYLLUM  cornicnlum 4, 1O4 

Davidsoni 1  o  | 

rugosum 1O4 

n.  sp 1O4,  1O5 

CYPHASPIS 93 

brevimarginatus 93 

CYPRICARUELLA iso,  250 

C YPRICARDIA  occidentalis 225 

?rigida 176 

CYPRICARDINIA ]82 

indenta 183 

inflata 182 

CYPRICARDITES  indenta :82 

CYETIA  Hamiltonensis 147 

CTHTINA 146 

Davidson! 146 

Hamiltonensis    146,147 

beteroclita 146,147 

C  YRTOCERA8 203 

cessator 278 

Nevadensis 3O3 

sp.  ? 

(Gompboceras)  Metula 203 

CYRTOLITES 84 

sinuatus 84 

CYBTID 273 

CYSTIPHY'.LUM  Americanum 1O6 

n.  sp 1O6 

CYTHERODON 181 

(Scbizodus)  quadrangularis 181 

DALMANITES 208,273: 

ancbiops 209- 

Meeki 3OS,  211 

micrurus 209 

undt.sp 21O 

262 
135 
135 
281 


DAWSOXKLLA  Meeki 

DELTHYRIS  raricosta 

undulatus 

DENTALIUM  (like  D.  primarinm) . 
DEVONIAN - --- 

Corals  not  illustrated 

Summary  of  fauna  of 


290 


INDEX. 


DEVONIAN— Continued. 

Fossils  of 99 

Ichthyio  fauna  of 7 

Number  of  genera  and  species  in 9 

DICELI.OCEPHALUS 40,89 

angustifrons 43 

bilobaius 4O 

?  expansus 45 

finalis 3,71,89,90 

flabellifer 268 

inexpectans 3, 9O 

lole 43 

Marica 44 

nasntns 4O 

Osceola 3,40 

quadriceps 45 

Richmoudensis 41 

DiPHYniYLLUM  Simcoense 1O5 

DISCIXA 112,213 

conuata 214 

Lodensis 5, 113,113 

media  112,113 

minuta 113 

Missouriensis 213 

N</wberryi 8,313,214 

nitida 113,313,214 

sp.  ? 113,268,279 

(Orbicula)  Newberryi 213 

DYSTACTELLA 172 

insularis 173 

subnasuta  173 

ECCULIOMPHALUS 187 

Bucklandi 187 

Devonicus 187 

minor   187 

ECHIXODERMATA 212 

EUMONDIA 245 

?  bicarinata 176 

Burlingtonensis  245 

?  circularis 346 

Medou 345 

Pinonensis 164,  277 

ESDOCEKAS  multitubulatum 87 

proteiforme 86 

EUOMPHALUS 185,  255 

conies 186 

Eurekensis 185 

laxus 186 

rugosus 255 

sp.? 277 

(Ecculiomphalus)  laxus 186 

^Phanerotinus)  laxus 186 


EUOMPHALUS— Continued. 

(Straparollus)  Hecale 186 

(Straparollus)  subrugosue 355 

FAUNA,  Devonian,  Summary  of o 

Fresh-water,  in  Lower  Carboniferous 8 

Ichlhyic,  of  the  Devonian 7 

of  Lower  Pogonip  group,  relations 4 

of  Middle  Pogonip  group 3 

of  Upper  Pogonip  group,  like  Lower  Trenton  ...  3 

Pecularities  of  "White  Pine  shale 5 

Passage,  between  Cambrian  and  Silurian 3 

FAVOSITES?  Argus 101 

basaltica j  QO 

bemispherica 1OO 

n.sp 1O1 

FKXKSTELLA  sp.  1 274, 279 

FlBTULIPORA  sp.  ?   1O1 

FOSSILS,  Cambrian n 

Carboniferous 212 

Devonian 99 

Lower  Silurian 03 

Potsdam,  of  Wisconsin,  occurring  in  Nevada 3 

FrsitiXA  c.vlindrica 279 

robusta 279 

GASTEROPODA  73, 182, 254 

GENERA  AND  SPECIES,  Number  of,  in  Paleozoic  forma- 
tions of  Central  Nevada  9 

GEOLOGIC  HORIZON,  Table  showing  number  of  gen- 
era and  species  in  each,  in  Central  Nevada 9 

GLYPTODESMA  sp.  ? 276 

GOMPHOCEBAS 202 

oviforme 202 

raphanus 202 

suboviforme  3O3 

sp.  ? 281 

GONI  ATITES 203 

desideratus 3O3 

Kingi 278 

sp.?  278 

GOXIOPHORA    ^ 171 

pcrangulata 1 71 , 195 

GRAMMYSIA 174, 244 

arcuata 8,  226,  345 

Hannibalensis     8, 175, 226,  344 

minor 174 

(Leptodomus ?)  arcuata 245 

GRAPTOLITHUS  sp.  ?! 270 

GRIFFITHIDF.S 266 

Porttocki  366 

GROUP,  Pogonip 65 

Prospect  Mountain 11 

GYPIDULA,  snbgenus 159 

occidentals 159 


INDEX. 


291 


Page. 

HALYSITES  catenulatus 4,273 

HAMILTON  GROUP  SPECIES 7 

HELICOTOMA 81 

planulata  81 

imiai)  u'ulat  a 81 

sp.  ?.... 81 

HEMIPRONITES  Chemungensis  var.  arctostriata 117 

HIPPARIOXYX  (Ati-ypa)  consimilis 150 

HYOLITHES 23,85,199,264 

aclis 199,264 

carbonai  la 264 

novellas 264 

primordialis 3, 23 

Vanuxemi 85 

sp.? 199 

(Theca)  primordialis 23 

ICHTHYIC  FAUNA,  Devonian,  in  Kanab  Canon 7 

ILL^ENURUS 97 

convexus 97 

Eurekensis 3,71,97 

quatlratus 97 

sp.? 269 

I L  UES  US 

crassicauda 79,272 

sp.  ? 272 

IXOCEHAMUS  Chemungensis  168 

oviformis 169 

Ii'HiUEA  bella 21 

Labiadoricus 19 

.'.'  sculptilis 17,20 

ISCH ADITKS  tcssellatus 67 

KUTORGIXA 18 

cingulata 19,21 

minutissima 20,21 

Prospectensis 19 

sculptilis 2O,21 

Whitfleldi 18 

LAMELLIBRANCHIATA 76, 164, 225 

LFJOPTERIA 166 

Rafinesquii .' 164, 166 

LEIOUH  YXCH  us 157 

multicostatus 159 

sinnatus 158 

LF.l'ERDITIA 88,206 

bivia 88 

Canadonsis 88 

rotundata - 2O6 

sp.?  -.  271 

LEPTjEXA '• 22 

Melita 3,22 

sericea 273 

LEFTOCCELIA  ftp.  ? - 276 


Page. 

LEPTODESMA 167,234 

complanatum 234 

naviforme 1C7 

Kogersi 234 

transversa 167 

8P? 234 

LlMOPTERA 167 

sarmenticia 167 

LLNGULA 13,106 

affinis in 

Alba-pinensis 1O8 

anatina m 

Elder! m 

LiBna 5.1O6 

Ligea 107,108 

Ligea  var.  Kevadensis 1O7 

Louensis 108 

Lucrctia 108 

?  mauticula 3,13 

Mclie 108,274 

mytiloides 108,279 

squamiformis 109 

White!  5, 1«9,  111 

sp-  1 : 270,274 

LlNGULEPIS 12 

Mffira .3, 1«J,  13 

ralnuta 3, 13 

LOWER  SILURIAN,  Fossils  of 65 

LOXONEMA 190, 258 

approximatum 191 

bella 258,259 

ceiithifbrmis 258 

Eurekensis 19O 

nobile 190,192 

styliola 191 

subattenuatum 190,  191,  192 

&P-? 192,278 

LUCINA  (Paracyclas)  elliptica  var.  occidentalis  .....         178 

LUNULICARDIUM  fragosnm 5,164,277 

MACLUREA gl 

acuminata 83 

annulata §1, 82 

carinata 82 

minima gi 

subannulata 83 

sp.?    83 

M ACROCHEILUS  Altonensis 260 

sp.? 260 

MACRODON 243 

Hamilton® 8,226,243 

parvus 244 

tenuistriata 8, 226, 280 


292 


INDEX. 


Page. 
MACRODOX— Continued. 

truncatus 243 

HARTINIA,  subgenua 139 

MEGAMBONIA 173 

occidualis 173 

subcordiformis 173 

ilEXOCEPHALUS  Sedgwicki --  51,  C4 

MERISTELLA 148 

Elissa 148 

nasuta 148,149 

tniuida I49 

(Wliitfieldia)  nasuta 148 

METOPTOMA 83,195,260 

?  analoga 84 

?  Devonica 195 

Phillips! 83,84 

peroccidens  26O 

perovalis 

Treutonensis ---  84 

MICKOUON 180,250 

complanatus 1 go 

(Cy  pi  icardella)  bellistriatus 250 

(Cypricardella)  connatus 25O 

(Cypricardclla)  gregarius 250 

(Cypi  icardilla )  macrostriatus ISO,  250 

MODIOLA  .  239 

?Nevadensis 239 

MODIOLOPSIS 77 

mytiloides 77 

occidens - 77 

Pogonipensis 78 

sp.?    270 

MODIOMORPHA 109,239 

alta 170 

altifonne 1®® 

ambigua 239 

desiderata *4O 

Hyalea 240 

lingniforinis 170 

oblonga 1TO 

obtusa 1*1 

/Pintoousis *4O 

quadrnla 171 

MOXOPTERI A  Marian 225 

MOXTICULOPORA sp.?  270,273 

MUHCHIBOXIA 79 

bellicincta 80 

bicincta — 79 

gracilis 

Milleri »9 

sp.? 271 

MYALINA    237 

anculata 237 


Page. 
MYALIXA— Continued. 

ampla 238 

Apacbesi 225,237 

aviculoides 225 

congeneris 237 

Nemesis 237 

•  Nessus 238 

Perniiana 225 

St.  Ludovica 237 

ml H | uad ra t a 237,  238 

?Swallovi 225 

sp.? 225 

MYTILARCA 168 

Chemungensis  1O8 

dubia 168 

oviformis 169 

sp.? 276 

(Plot  homy  t  ilus)  ovifoi  mis 168, 169 

MYIILUS  Chcniungensis 108 

NATICOPSIS  (like  X.  wquistriata) 278 

»!'••' 278 

XAriiM's  (like  X.  digonis) 281 

XUCLEO6PIRA 147 

couciniia  147 

NUCULA 172,241 

nrata 225 

bi'llistriata 241 

insularis 241 

?  le  vata 242 

levatifortne 241 

Xiotica 172 

Kcscuensis 172 

varicosa 241 

sp.; 172 

NUCULITES  triangulus 277 

XYA6SA 173 

parva   173 

recta 174 

OBOLELI.A 14,67 

?ambigna 3,67,68 

cbromatica 68 

desiderata 68 

desquamata 68 

discoidea 3, 14 

68 

...  68 

68 


gemma 

polita 

sagit  tails 

Salteri t. 

?  SoabriniE 

sp.? 

OGYOI  A 

?  probleinatica 

?  spinosa 


17 
270 

3G 
63 
63 


INDEX. 


293 


Page. 

OLEXELLUS 28 

nsaphoides 36,37,38,39 

Gilbeiti 2,  29,  34,  36,  37,  38 

Howelli 2,  3O,  31,  32,  33,  34,  35,  37, 38, 39 

Iddiugsi 28,30,37,38 

Thompson! 38 

Vermontana 34,38 

OI.EXUS  (Olenellns)  Gilbert! 29 

(Olenellus)  Howelli 30 

ORBICULA  Lodensis 112 

nnnuta 112 

nitida 213 

ORTHIS....! .22,72,114 

Eurekensis 22 

ftssicosta 73 

Hamlmrgensis 3,  73 

iuipressa 4, 115,  169 

uu-qualis 117 

insignis 116 

lovrensis 115 

Lonensis  74 

McFarlanei 114,115 

occidentalis 74 

Pecosi 279 

perversa 117 

perveta 4,72,79 

plicatella 73 

Pogonipensis 270 

IIV;;YUS 117 

rosupinata 3,  279 

testudinaria 1, 4,  72, 73,  78 

triofiiaria 4,  74,  78,  79 

Tullicnsis 4, 115 

sp.? 268,273 

ORTHISIXA  arctostriata 117 

altemata 117 

ORTHOCERAS 200,260,265 


annulato-costatum 

Bcbryx 

bonuiu 

cliuocameratam — 

Eurekensis 

exile ... 

multicameratum. . . 

Randolphensis 

Tboas    


265 

201 

87 

266 

265 

201 

86 

265  i 

201 

.86,87,266,273 


OliTHOCKRATA   

ORTHO.XOTA  ventricosa 

PACHYPHYLLUM  "Woodmani 

P  ALJEOMAXON 

cratera 


177 
105 


PAL^OMANON— Continued. 

Romeri 

PARACYCLAS , 

dliptica  var.  occidentalis 


Page. 

99 

178 
178 


occidentalis 164,165,178 

peroccidens 277 

PARADOXIDES 39 

Kj  erulfl . .-. 39 

PECTER?  pnsillus 231 

PENTAMERUS 159 

biplicatus .162 

comis 159,102 

galeatiforni 159 

galeatus 114, 161 

Lotis 161, 1C2 

occidentalis 159,160 

snbglobosus 162 

PHACOVS - 207 

bombifrons 207 

rana 5,207,211 

PHAXEKOTIXUS  paradoxus 186 

PHILUPSIA 211 

coronata 211 

Lodensis 267 

(Brachyinetopus  ?)  ornata 211 

(Grifflthidcs)  Portlocki 266 

PHOLIDOPS  113 

bcllula 113 

Hamiltonaj '. 11 3 

ovalis 113 

quadraugnlaris 114 

PHYSA 202 

prisca - 262,263 

PINNA - 235 

consimiiis 236 

flexicostata 236 

inexpectans 235 

Ludlovi 225 

Missouriensis 236 

peracuta? 225 

spatula 236 

subspatula 236 

PLATYCE  RAS 182, 254 

acutirostris 255 

carinatum 182,184,195,254 

conicum 182 

Conradi 182,  184 

dtntalium 182,195 

dumosum 183 

dumosam  Tar.  rarispinnm 183 

Newberryi 184 

nodosum..  182,183 


294 


INDEX. 


PLATYCEHAS— Continued. 

occidens 

Piso  

symmetricuni 

thetiforme  ... 


Page. 

254 

254 

183 

184 

Thetis 182, 183, 184 

undulatuni 184 

PLATYOBTOMA 185, 255 

inornatus 255 

lineatum 5, 184, 185,  255 

sp.?  277 

PLATTSCHISMA 188 

?  ambiguum 1 8S 

applanatua 188 

?McCoyi 188 

sp.?  277 

PLETHOMYTILUB,  snbgenus 16D 

oviforniis 169 

Pl.EUKOPHOItUS 240 

costatus 246 

Meeki 246 

subcostatus 225 

Pl.EUROTOMAKIA 80, 259 

Lonensis  SO 

Kasoni 78 

Js  evadensis . .  259 

nodoniarginata 8,  24.".,  259 

sp.  .'   "271,  277,  281 

PLUMUUTFS 88 

PtECii-Ol'OUA 24,  89,  207,  260 

Poaoxir  Group r."> 

POLYl'OEA  sp.  ? '-7!) 

PouAMp.oxiTES  obscura 27u 

POK1FEKA    H,  !)!> 

PosinONiA  ?  arcuata    245 

POSIUONOMYA    178 

Bromii   170 

DC vouica 1 79 

lan-is irs 

POTSDAM  FOSSILS  of  Wisconsin  occurring  in  Nevada.  3 

PliOPLCTELLA 128 

l.ichrymosa  var.  lima 132 

Licbry  mosa  var.  stigmata 132, 133 

ir.ivicclla    — 131 

Slnnnardianua 129 

spccioaa 133 

trnncata 131 

PKOPUCTUS 128,214 

ciincentricus 129 

Cora 215 

costatus 279 

dissimilis..            130 


Page. 
PRODUCTUS— Continued. 

elegans 215,279 

hirsutus 134 

hirsutiforme 133 

lachrymosus  var.  limus 169 

lachrymosus  var.  stigraatus 169 

longispinus 279 

longispinus  var.  muricatus  279 

Murchisonianus 132 

muricatus 215 

navicellus  131 

N  ebrascensis 279 

Prattenianus 279 

punctatus 279 

pustulosus 131 

pyxidatus  12!) 

sriiiirecticulatns   .'.     21"i,  279 

Shumaidianus    129,131 

s|M'ci«>sns    133, 169 

sjiiiiulicosta? '. 129 

subaculeatus 5, 195,  21 4 

truuratus 5,131 

sp.  ? 132 

(Productvlla)  dissimilis    130 

(Productella)  Hallanus 13O 

(Prodnctella)  lachrymosua 132 

(Productrlla)  Lieliryniosus  var.  liuins 132 

(1'iinhictflla)  liirbryniosiis  var.  stiuiuatus   132 

i  I'Hi.Inctclla)  navicfllus 123,131,132 

(Productclla)  pyxidatus  130 

il'iodnctella)  Sliinuardiauus 12S,  I2;>,  132 

i  I'lcidnctfll  i)  spcciosiiH 133 

(Productella)  subaculwitus  12>.  l:n,  1:12 

(Productclla)  truncatus 123,  131 

(Stropbalosia)  Murcliisouiauus 131, 132 

PliOhTUS 210 

clarus 211 

decorus 35 

Haldeuianni 5,  21O 

marginalia 5,  21O.  211 

venustus 35 


sp. 


PROSPECT  MOUNTAIN  GROUP 11 

PROTOSPONGIA 11 

fi.-neat.ra ta  2, 1 1 , 12 

sp.  ? 268 

PTERINEA 165,234 

flabella 5,164,165,171 

Cbemungensis 100 

Newarkensis 165 

Pintoensis 234 

PTERIXOFECTEN  232 


INDEX. 


295 


Page. 
PTEKIXOPECTEN— Continued. 

exfoliatus 233 

Hoosacensis 232 

Spio 233 

si)..'   276 

(Pecten)  papyraceus 233 

1'TEKOCEPHALUS 58 

PTEROPODA 23,85,196,264 

PTILODICTYA  carbonaria 8 

serrata 8 

sp.  ? 270,279 

PTYCH  ASPIS 60 

minute  3,6O 

pustuloaa 269 

PTYCHOPARIA   46,91 

affinis 3 

Tangnlatua 269 

?  annectans 91 

Anytus 56 

fiilyuienoides 48 

rentralis 55 

Eos 51 

Gallatinenais 27,55,57 

granulosus 3,  57 

Hagnei 3,  57 

Iseviceps 54 

?  Linnarssoni 2,  47 

macnlosus 269,271 

minor 91 

minutua 91 

Montanensis 53,  56 

nitidus 57 

Oweni ' 3,17,20,55,71 

occidentals 51 

?pernaautus 49 

]>lanns 56 

>  Prospectensis ?,  46,  48 

siniilis 52,53 

piroilis  var.  robuatus 53 

striatus 48 

rmisulcatus 3,  58 

sp.? 269 

(Euloma  ?)  affinia 54 

(Enloma?)  dissimilis 51 

(Pterocephalns)  laticeps 59 

( Pterocephalus)  occidens 58 

(Solenoplenra)  breviceps 49 

PTYCHOPHYLLUM  ?  infundibulum 274 

PTYCHOPTERIA 235 

Proto 235 

protoforme 235 

sinuosa 235 


Page. 

PULMONIFKKA 261 

PUPA  Bigsbyi 262 

Vermillionensis 262 

vetusta 262 

EAPHISTOMA 78 

Xasoni 4,78,79 

sp.? 271 

(Pleurotomaria)  "Nasoni 78 

RKCEPTACULITE8 05 

ellipticus 67 

elongatus 66,  67 

fungosum 06 

infundibulus C7 

insnlaris 66 

Jonesi 66 

mammillaris 4,  65,  C6 

Keptuni C6 

RECURRENT  SPECIES,  Number  of 9 

RESULTS.  Summary  of 1 

RETZIA  -'-         220 

compressa 220,  221 

Marcyi 220,222 

Mormoni 220,221 

punctulifera 220,  221 

rartialis 5,220,221,222 

radialis  var.  grandicosta 221 

subglobosa 220 

vera 220,222 

Verneuiliana 220,222 

RHIZOPODA 65 

RHYNCHONELLA 152,223 

alte 156 

castanea 153, 154, 155 

Cooperensis  224 

cuboides 154, 137 

duplicata  155,157 

Emmonsi 154,157 

Eurekensia 223 

Horsfordi 152 

intermedia 157 

?  Laura 159 

Misaouriensis 156 

?  occidens 1 52 

pugnus  155, 159 

reniformis 156 

sinuata 169 

Tethya 152 

Thera 223 

venustula 154, 157 

sp.? 280 

(Leiorhynchus)  Kelloggi 158 

(Leiorhynchns)  Laura 157, 159 


296 


INDEX. 


Page. 

EHYNCHONELLA— Continued. 

(Leiorhynchus)  Nevadensis 157 

(Leiorhynchus)  quadricostata 5 

(Leiorhynchus)  sinuata 158 

(Stenocisma)  duplicata 155 

(Stenocisma)  Horsfordi 152 

(Stenocisma)  Tethys 152 

SANGUIXOLITES  175,247 

JEolus 8,220,347 

?  Combensis 175 

?gracilis 175 


perangulatus  ...................................  J  ~  ! 

retusus  .........................................  2*7 

rigidus  ____  ..........................  5,164,169,176,247 

Salteri  .......................................  :--  8-1  S 

?  Sanduskyensis  ...........................  164,170,176 

simplex.  .    ......................................  a48 

striata  ..........................................  '**9 

ventiicosus  ..................................  5,164,177 

SCEXELLA  ...........................................  15 

?conica  .  .  .......................................  *5 

reticulate  .......................................  15 

SCHIZAMBON,  n.  gen  .................................  6* 

typicalis  .....................................  3,  7O 

S(  IIIZODUS    ........................................  181,252 

cuneatus  .......................................  245,  2.  3'J 

ciuieus  ..........................................  -:'4 

cnrtiforme  ......................................  253 

cuvtus  ........................................  -•"'•' 

deparcus  ........................................  258 

Pintoensis  ......................................  *•»:« 

Eossicus  ........................................  -:':; 

Wheeleri  .......................................  225 

(Cytherodon)  orbicularis  ........................  181 

SCOLIOSTOMA  ........................................  195 

Americana  ......................................  19.5 

Daimenbergii  ..................................  195 

SEIH.WICKIA?  concava  ..............................  225 

SERPULA  (Spirorbus)  planorbites  ....................  255 

SiiiLritiAX  ............................................  65 

Corals  not  illustrated  .....  .-  ......................  7 

Lower.    Fossils  of  ..............................  65 

Number  of  genera  and  species  in  ................  9 

SIPHOXOTRETA  ......................................  69 

flssa  ............................................  70,71 

unguiculata  .....................................  16 

SKEXIDIUM  ...................................  ......  116 

Devonicum  ....................................      116 

insignis  .........................................  .  116 

S.MITHIA  Hennahii  ..................................  274 

SOLEXOMYA  .........................................  242 


SOLENOMYA—  Continued. 

curta 
SPIRIFER  cuspidatns? 

increbescens 

Kentuckensis 

neglectns 

octoplicata? 

Parryanus 

spinosus 

trigoiialis 


Page. 

242 

219 

215 

218 

217 

218 

137 

218 

215 

nndiferus 143, 144 

varicosns 136 

(Trijjonotreta)  Pinonensis 138 

SPIRIFERA 134, 215 

annectaus 216 

arctisegmenta 136 

bifurcata 216 

bisuleata 215 

catneratd 215,  279 

compacta 143 

crassa 215 

desiderata 217 

(lisjimcta 134, 169 

duodenaria 135 

Eugleraani 13S 

ernbescens 145 

limbriata 143 

grandicostata 21~> 

Kemiicotti 134 

Kentuckensis  var.  propatula 218 

Keokuk  6 

laminosa 218 

Leidyi 216,217 

macronata 218 

Maia   141 

Manni 137 

Marcyi  i1!,* 

mesastrialis 137 

neglecta 21 7,  220 

Norwoodi 134. 

octoplicata 21* 

Pariyana 137 

Pinonensis 13S 

raricosta 135 

Eockyraontana 6, 215,  279 

segmenta 136 

striata 279 

strigosa 275 

subumbona 141 

subimdif era 143 

transiens 215 

t  rigonalis 215 


INDEX. 


297 


Page. 
SriuiFERA— Continued. 

undifera 143,195 

unilifera  var.  Takwanensis 143, 145 

TTt  ahensis 134 

varicosa 123, 136 

sp.  undt 137 

(Martinia)  coiupacta - 144,145 

(Martinia)  curvatus  var.  undulata 145 

(Martinia)  Franklini 139,140 

(Martinia)  fimbrinta 143, 145 

(Martiuia)  glabra 139,140 

(Martinia)  glabra  var.  Xevadensis 139, 144, 145 

(Martinia)  Isovis 140 

(Martinia)  Ircvis  =  glabra 145 

(Martinia)  lineata 141 

(Martinia)  Maia 141,142 

(Martinia)  meristoides 141,142 

(Martinia)  ovalis 14.") 

(Martinia)  ]>ingui* 145 

(Martinia)  planoconvexa  141 

(Martinia )  pra-matura 144,  145 

(Martinia)  pseudolineata 144, 145 

(Martinia)  Richardson! 143, 144 

(Martiuia)  si/tigera 144, 145, 140,  279 

(Martinia)  sublineata 141,142 

(Martinia*  subnmbona 142 

(Martinia)  subundifera 143, 145 

(Martinia)  undifera 140, 141, 143, 144, 145, 140 

(Trigouotreta)  argentarius 138 

(Trigonotreta)  Pintoensis  138 

SPIF.IFKRIXA 218 

ciistata 5,218,219 

insculpta 219 

Keutuckensis 218,  219 

Kentnckensis  var.  propatula 218 

octoplicata 218,219 

spinosa 218 

Sriuic.ERA  ( Atbyris)  hirsuta 222 

SPIRIGERI.NA  ?  radialis 220 

•  STF.XOTIIECA 23 

elongata 23 

STRAPAROLLUS 187 

Xewarkensis 187 

>,,.; 271 

(Euotnjihalus)  rugosus 256 

(Euomphalus)  subrugosns 256 

STHF.r.l.Ol'TERIA 230 

hi'vigata 231 

similis 230 

tenuilineata 231 

STP.F.PTELASMA,  n.  sp 273 

STREPTOKHYXCHU8 75,  117 


Page. 


STREPTORHYNCHUS—  Continued. 
Chemungensis  ................  .. 

Chemungensis  var.  A,  S.Pandora 
Chemungensis  var.  B,  S.  arctostriatus 
Cbeniungensis  var.  C,  S.  perversus 
Chemungensis  var.  D,  S.  pectinaceus 
Cbeniungensis  var.  Pandora 
crenistria 
minor 
Pandora  ... 
sinuatus 
STUOMATOPOUA 


117 
117. 
1  17 
117 
118 
279 
75 
117 
75 
100 
sp.  ?  ..................................  ..........         274 

STKOPHITKB  grandseva    .............................      8,262 

STROPHODOSTA  .............................  :  ........         118 

atnpla  ..........................................  118,121 

arcnata  ....................................  ----       121 

Calvini  ................  ........................      122 

canace  ....................  -  ....................          275 

demissa  .......................  .................  118,119 

dimosa  ?  ........................................          118 

fragilis  .....................  .  ...................          120 

inequiradiata  ..................................      1  2O 

Patersoni  ....................................  5,119,120 

perplana  .......................................  118,120 

punctulifera  ....................................       121 

quadrata  ........................................          122 

STROPHOMENA  ......................................    71,118 


arctostriata  .....................................  117 

bifni  cata  .......................................  117 

Cbemungensis  ..................................  117 

crenistria.  .......................................  120 

deltbyris  ........................................  120 

demissa  ........................................  118,119 


gibbosa 

inequiradiata 

inequistriata 

lima 

mucronata 

Kemea 

uervosa  

Patersoni : 

pectinacea 

perpl-na 

pluristriata 

pustulosa 

rbomboidalis 

setigera 

(Stropbodonta)  demissa , 

(Stropbodonta)  inequiradiata 

(Stropbodonta)  Patersoni 

STYI.IOLA 


123 
120 
120 
132 
124 
71 
120 
119 
117 
120 
120 
131 
US 
125 
119 
120 
119 
197 


298 


INDEX. 


Page. 

STYUOLA—  Continued. 

clavnlus  

198 

fissurella  

197,198 

flssurella  var.  intermittena  

19V 

SYMPHYSURUS  

S5 

?Goldfus8i  

95 

SYKINGOPOBA  Hiaingeri  

4,1O3 

perelegans  

5,103 

multat  temiata  

279 

SYRIXGOTHYHIS  

2!9 

cuspidata  

.219,220 

TELLINOMYA  

76 

contracts  

4,76 

?  Hainburgenpis  

3,76 

protensa  

225 

(Ctenodonta)  astartajformis  

77 

(Ctenodonta)  varicosa  

77 

TEXTACULITES  

196 

attennntus  

197 

!  (  Ihilns  

197 

j,rracil.striatus  

196 

sralariformia  

197 

TEHEBKATULA  

224 

anisodonta  

155 

boviilens  

"Ml 

liastata  

224 

iiinntifeo  

220 

Mormoni  

220 

TEKEBRATTLA—  Continued. 


pugnus 
radialis 


TEREBUATULITES  criatatua  . 
THAMMSCLS?  sp.  ?...  ...... 

THECA  priruordialia  ........ 

THECI  A  i  ainosa  ............ 

TREMATOSPIRA  ............. 

caiuura  .  . 


155 

220 

276 

218 

274 

23 

1O2 

151 

151 

infrequens 151 

gibbosa 151 

TRILOHITE,  Supposed  eggs  of 211 

TniNLTLfcUS  concentricus 273 

TRIPI.ESIA 75 

calrifera :i,  75 

TnopiDOLKPTfB  carinatus 276 

UPPER  HELDERBERO  HORIZON  of  New  York,  Num- 
ber of  sperirs  rciircscnting 7 

WHITE  PINE  SHALES H 

Straligrapliic.  ])o.sii  ion  of .'i 

WIIITFIELUIA 14> 

tuniida 149 

AVIWOXBIX,  Potsdam  fossils  of,  occurring  in  Xcvada  .'! 

XAPIIRKXTIS  ?  sji.  ? 27::,  27!) 

ZAPIYCHIUB 263 

cai'bouaria 261,263 

ZOXITES  (Connulus)  Priscua 2C2 

ZYGOSPIRA  Headi i  :»o 


PLATE    I. 

Page. 
ACROTRETA   GEMMA 17 

Fig.  1  a.  View  of  the  posterior  side  of  the  ventral  valve,  enlarged  to  six  diameters. 

1 6.  Cast  of  the  interior  of  the  apex  of  the  ventral  valve,  showing  a  cast  of  the  sipho- 
nal  tube  and  the  elongate  muscular  scars,  enlarged  to  six  diameters. 

1  c.  Interior  of  the  dorsal  valve  of  Oboltlla  f  Scalrince  Callaway  (after  Davidson). 

1  d.  Interior  of  ventral  valve  enlarged  to  six  diameters. 

le.  Exterior  of  a  small  dorsal  valve,  enlarged  to  six  diameters. 

If.  Interior  of  apex  of  ventral  valve. 
See  plate  ix,  figs.  9,  9 a. 

OBOLELLA  ?  AMBIGUA 67 

Fig.  2  a.  Dorsal  valve  with  the  central  portion  of  the  shell  exfoliated  so  as  to  show~the 

median  muscular  scars,  enlarged  to  three  diameters, 
y  6.  Exterior  of  ventral  valve,  enlarged  to  three  diameters. 
2c.  Interior  of  dorsal  valve,  enlarged  to  three  diameters. 

SCHIZAMBON   TYPICALIS 70 

Fig.  3.      Interior  of  ventral  valve,  enlarged  to  six  diameters. 

3  a.  Exterior  of  ventral  valve,  enlarged  to  six  diameters. 
30.  Interior  of  dorsal  valve,  enlarged  to  six  diameters. 
3c.  Exterior  of  dorsal  valve,  enlarged  to  six  diameters. 

3d.  A  portion  of  the  siirface  of  fig.  3c,  enlarged  to  show  the  minute  surface  spines. 

METOPTOMA  PHILLIPSI 83 

Fig.  4.     View  lookiug  from  above.    Natural  size. 

4  a.  Side  view  of  same  specimen. 

MODIOLOP8IS  OCCIDEN8 77 

Fig.  5.      Cast  of  tho  right  valve.     See  plate  xi,  figs.  14, 14  a. 

MODIOLOPSIS  POGONIPENSI8 78 

Fig.  6.      Cast  of  the  left  valve.    See  plate  xi,  fig.  13. 

KUTORGINA  8CULPTILIS 20 

Fig.  7.      Upper  surface  of  ventral  valve,  enlarged  to  six  diameters.    This  fignre  is  drawn 

from  the  type  specimen  from  Montana,  described  by  Mr.  Meek. 
7  a.  Posterior  view  of  the  same  to  show  elevation,  area,  and  deltidial  opening 
7  fc.  Enlargement  to  six  diameters  of  a  specimen  from  the  Eureka  District.     See  plate 
ix,  fig.  7. 

SlPHONOTRETA  UNGUICULATA 69 

Fig.  8.      Interior  of  ventral  valve  (after  Davidson).     Introduced  for  comparison  with  the 
ventral  valves  of  Acrotreta  and  Schizambon. 

PTYCHOPARIA  ?  SIMILIS,  var.  ROBUSTUS 53 

Fig.  9.     View  of  the  central  portion  of  the  head.     Natural  size. 
9  a.  Outline  of  profile  view  of  the  same. 

DlCELLOCEPHALUS  INEXPECTANS 90 

Fig.  10.    Central  portions  of  the  head  of  a  small  specimen.    Natural  size. 

METOPTOMA  ?  ANALOGA 84 

Figs.  11,  11  a.  Summit  and  side  view  of  the  type  specimen.    Natural  size. 

MURCHISONIA  MlLLEttl 271 

Figs.  12,  12  a.  Front  and  back  view  of  the  same  specimen.    Natural  size. 
12  b.  View  of  a  cast.    Natural  size. 

BUCANIA  BIDOR8ATA 271 

Figs.  13,  13a,  13c.  Back,  lateral,  and  front  view  of  a  specimen  denuded  of  most  of  the  shell. 

Natural  size. 

13ft.  Enlargement  of  the  surface  of  another  shell,  that  shows  the  characteristic  sur- 
face lines. 


t'NITl.n   STATES    GEOLOGICAL   SURVEY 


PALEONTOLOGY    OF   THE    EUREKA    DISTRICT       I'L.    I 


I/ 


2a 


I-1 


CAMBRIAN    AND    SILURIAN 


PLATE    II. 

Pag*. 

LINGULA  ALBA-PINENSIS 108 

Fig.  1.     Broad  form,  enlarged  to  six  diameters. 
Ic.  Elongate  form,  enlarged  to  six  diameters. 

LINGULA  LIGEA 107 

Fig.  2.  A  typical  specimen,  enlarged  to  two  diameters. 

LINGULA  LIGEA,  var.,  NEVADENSIS 107 

Fig.  3.  Specimen  showing  the  more  attenuate  form,  as  compared  with  fig.  2.     Enlarged  to 
two  diameters. 

LINGULA  MELIE 274 

Fig.  4.  A  distorted  specimen.    Natural  size. 

DlSCINA  LODKNSIS 112 

Fig.  5.      Ventral  valve.    Natural  size. 

5  a.  Dorsal  valve.    Natural  size. 

PHOLIDOPS  BELLULA 113 

Fig.  6.     Ventral  valve,  enlarged  to  six  diameters. 

6a.  Cast  of  interior  of  ventral  valve,  enlarged  to  six  diameters. 

6  b.  Interior  of  ventral  valve,  enlarged  to  six  diameters. 

PHOLIDOPS  QUADRANGULARIS 114 

Fig.  7.     Enlargement  to  three  diameters  of  the  type  specimen. 

CHONETES  DEFLECTA 124 

Figs.  8,  8  a,  86.  Medium,  transverse,  and  short  forms  of  the  ventral  valve.     Natural  size. 

STROPHODONTA  DEMISSA 118 

Figs.  9,  9a,  9  6.  Lateral,  ventral,  and  dorsal  views  of  a  specimen  from  Lone  Mountain. 

PRODUCTUS  IIIRSUTIFORME ." 133 

Fig.  10.  Enlargement  to  three  diameters  of  a  small  ventral  valve,  preserving  three  of  the 

slender  surface  spines. 

10 a.  A  large  ventral  valve,  showing  a  portion  of  the  outer  shell  and  cast  of  the  inner 
surface. 

STROPHODONTA  INEQUIRADIATA 120 

Fig.  11.     A  strongly-marked  fragment  of  the  ventral  valve. 
11  a.  Enlargement  of  the  surface  of  fig.  11. 

ORTHIS  TULLIENSIS 115 

Figs.  12, 12 a.  Lateral  and  ventral  view  of  an  average  size  specimen. 

CHONETES  MACKOSTRIATA 126 

Fig.  13.  Dorsal  view.     Natural  size.     See  plate  xiii,  figs.  14,  14a-c. 


UNITED    STATES    GEOLOGICAL   SURVEY 


PALEONTOLOGY   OF  THE  EUREKA   DISTRICT      PL.    II 


La 


-0 


lOa 


lla 


DEVONIAN 


PLATE    III. 

Page. 
SPIRIFERA  MAIA 141 

Figs.  1,  1  a.  Lateral  and  dorsal  views  of  young  shell,  showing  area  on  each  valve.    Natural 

size. 

1  6.  A  globose  form  with  a  lower  area  on  the  ventral  valve.     Natural  size. 
1  c.  A  similar  form  to  S.  (M.)  meristoidcs  Meek. 

1  d,  1  e.  Ventral  and  lateral  views  of  a  transverse  form,  with  a  high  area  on  the  ventral 
valve.     (S.  8M&wflifco«a-like.)    Natural  size.     See  plate  xiv,  figs.  13,  13  a. 

C  YRTINA  DAVIDSONI 146 

Figs.  2, 2 a, 2b.  Basal,  dorsal,  and  eide  views  of  a  strongly-plicated  specimen.    Enlarged 

to  three  diameters. 

2.c,  d,  e.  Views  of  area,  side,  and  dorsal  valve  of  a  smoother  shell.    Enlarged  to  three 
diameters. 

SPIRIFEKA  UNDIFERA,  var 143 

Figs.  3, 3  a,  b.  Dorsal,  ventral,  and  side  views  of  the  specimen  mentioned  in  the  text  aa  of 
the  type  of  S.  prcematura  Hall.  Enlarged  to  two  diameters. 

PENTAMERUS  COMIS 159 

Fig.  4.  Dorsal  view  of  a  typical  specimen  from  Independence,  Iowa.    Natural  size. 

7.  Same  view  of  a  smoother,  similar  form  from  Nevada.     See  plate  xv,  figs.  5,  5  a,  6. 

SPIRIFERA  GLABRA,  var.  NEVADENSIS 139 

Fig.  5.  Dorsal  view  of  a  less  transverse  specimen  than  that  figured  on  plat*  xiv,  fig.  14. 

SPIRIFERA  UNDIFERA 143 

Figs.  6, 6  a.  Dorsal  and  ventral  views  of  a  specimen  with  closely-arranged  cencentric  stria? 
crossing  a  few  low,  rounded  plications.  Natural  size.  SIM-  plate  xiv,  figs.  11, 
lla,b. 

MERISTELLA  (W.)  NASUTA 148 

Figs.  8, 8fl,  I.  Ventral,  dorsal,  and  side  views  of  a  well-marked  specimen.    Natural  size. 

PENTAMERUS  Lous 161 

Figs.  9,9  a,  &,  e.  Four  views  Sf  a  typical  specimen.     Enlarged  to  two  diameters. 


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la 


DEVONIAN 


PLATE    IV. 

Page. 
SPIRIFERA  PI^ONENSIS 138 

Figs.  1, 1  a,  I.  The  original  figures  of  S.  argentarius  Meek. 
1  c,  e,f.   The  original  figures  of  S.  Pinonensis  Meek. 

1  d.  Dorsal  view  of  a  specimen  from  the  Eureka  District,  in  which  the  radiating  pli- 
cations are  finer  than  in  fig.  1  e.    Natural  size. 

SPIRIFERA  RARICOSTA 135 

Fig.  2.      Ventral  valve  of  a  specimen  with  numerous  plications. 

2  a.  Same  view  of  a  shell  with  few  plications.     See  plate  xiv,  fig.  12. 

TREMATOSPIRA  INFREQUENS 151 

Figs.  3, 3  a,  b.  Dorsal,  ventral,  and  side  views  of  the  type  specimen.    Natural  size. 

CRYPTONELLA  PI^OXENSIS 163 

Fig.  4, 4  a,  b.  Dorsal,  ventral,  and  side  views  of  the  type  specimen.    Natural  size. 

MYTILARCA  DUBIA 168 

Fig.  5.     Cast  of  right  valve.    Natural  size. 
5  a.  View  of  anterior  side. 

POSIDONOMYA  L2EV1S 178 

Fig.  6.  Eight  valve.    Natural  size. 

POSIDONOMYA  DE VONICA 179 

Fig.  7.  Right  valve  enlarged  to  two  diameters. 

MODIOMORPHA  OBTUSA 171 

Fig.  8.     Cardinal  view  of  right  valve. 
8  a.  Right  valve.    Natural  size. 

MYTILARCA  CIIEMUNGENSIS 168 

Fig.  9.  Right  valve.    Natural  size. 

SANGUINOLITES  ?  GRACILIS 175 

Fig.  10.  Right  valve.    Natural  size. 


UNITED    STATES   GEOLOGICAL   SURVEY 


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PLATE   V. 

Page. 
MEGAMBONIA  OCCIDUALIS 173 

Fig.  1.  Left  valve.    Natural  size. 

ACTINOPTERIA  BOYDI 166 

Fig.  '2.  Left  valve.    Natural  size. 

LlMOPTERA   8ARMENTICIA ll>7 

Fig.  3.      Small  left  valve.    Natural  size. 
3  a.  Side  view  of  36. 
3  fe.  Large  left  valve.    Natural  bize. 

SANGUINOLITES  ?  SAKDUSK YENSIS 176 

Fig.  4.  Left  valve.    Natural  size. 

MlCRODOX  (C.)  MACROSTRIATU6 180 

Fig.  5.  Eight  valve.    Natural  size. 

PTERINEA  FLABELLA 165 

Fig.  6.  Left  valve.     Natural  size.     See  plate  xv,  fig.  12. 

MODIOMORPHA  OBLOXGA 170 

Fig.  7.  Left  valve.     Natural  size. 

SCHIZODU8  (C. )  ORBICUhARIS 181 

Fig.  8.     Cast  of  right  valve.    Natural  size. 

8  a.  Small  right  valve  with  a  more  strongly-outlined  postero-cardinal  angle. 

MODIOMORPHA  ALTIFORME 169 

Fig.  9.  Cast  of  right  valve.     Natural  size. 

LEIOPTERIA  RAVINESQUII 166 

Fig.  10.     Left  valve.     Natural  size. 

10  a.  Small  left  valve.     Natural  size. 

MYTILARCA  (PLETHOMYTILUS)  OVIFORMIS 169 

Fig.  11.  Cast  of  right  valve.     Natural  size. 

PTERINEA  NEWARKENSIS 165 

Fig.  12.  Cast  of  right  valve.    Natural  size. 
LEPTODESMA  TRANSVERSA 167 

Fig.  13.  Left  valve.    Natural  size. 

CYPRICARDINIA  INDENTA 182 

Fig.  14.  Left  valve.    Natural  size.    See  plate  xv,  fig.  11. 


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13 


DEVONIAN 


PLATE    VI. 

Page. 
SCOLIOSTOMA  AMERICANA 195 

Figs.  1,  la.  Two  views  of  a  specimen  showing  the  aperture  with  the  coluinellar  lip  broken 

away.  Natural  size. 
16,  c,  d.  Three  shells  showing  the  inturning  and  expansion  of  the  coluraellar  lip. 

Natural  size. 
1  e.  View  looking  down  on  the  apex  of  the  spire.     Natural  size. 

PLATYCEBAS  UNDULATUM 184 

Figa.  2,  2a.  Dorsal  and  side  views.    Natural  size. 

EUOMPHALUS  (P.)  LAXUS 186 

Fig.  3.  View  of  upper  side,  enlarged  to  two  diameters. 

PLATYCERAS  THETIFORME 184 

Figs.  4,  4  a,  b.  Posterior,  dorsal,  and  side  views  of  the  cast.    Natural  size. 

PLATYCERAS  NODOSUM 183 

Figs.  5,  5  a,  6.  Posterior,  dorsal,  and  side  views  of  the  cast  of  a  strongly-marked  specimen. 

Natural  size. 

ECCULIOMPHALUS  DEVONICUS 187 

Figs.  6, 6  a.  Dorsal  and  ventral  views  of  an  adult  shell.    Natural  size. 

LOXONEMA  APPROXIMATUM 191 

Fig.  7.  A  specimen  with  the  apex  imperfect.    Natural  size. 

HYOUTHES,  sp.  t 199 

Figs.  8,  80.  Two  views  of  the  only  specimen  obtained.     Natural  size. 

COLEOLUS  L^VIS 199 

Fig.  9.  A  fragment  of  shale  with  numerous  tubes  lying  upon  it,  enlarged  to  two  diameters. 


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DEVONIAN 


PLATE    VII. 

Page. 
DISCINA  NEWBERRYI 213 

Fig.  1 .  Lateral  view  of  the  specimen  figured  on  plate  xviii,  fig.  3. 

PRODUCTCS  SUBACULEATUS 214 

Fig.  2.  Ventral  valve.    Natural  size.    See  plate  xiii,  figs.  19,  20. 

DISCINA  CONXATA 214 

Fig.  3.     Ventral  valve.     Natural  size. 
3  a.  Side  view  of  fig.  3. 

DISCINA  NITIDA 213 

Figs.  4,  4  a.  Interior  of  compressed  ventral  valves,  showing  the  smooth  inner  surface  and 
rougher  outer  surface  marked  by  strong  concentric  strise. 

RETZIA  RADIALIS 220 

(A  series  to  illustrate  the  variation  in  the  number  and  size  of  the  radiating  surface  plica- 
tions, all  enlarged  to  two  diameters.) 
Figs.  5, 5  a,  Eetzia  Virneuiliana  Hall,  a  specimen  from  the  Lower  Carboniferoas  of  the  Little 

Belt  Mountains,  near  Clemlenin,  Montana. 
5  6.  From  the  Devonian  White  Pine  shale. 
5  c,  d,  e.  Lower  Carboniferous  forms  from  the  Eureka  District. 
5/>  9)  ^«  Upper  Carboniferous  forms  from  the  Eureka  District. 

RHYNCHONELLA  THKRA 223 

Figs.  6,  6  a,  b,  c.  Dorsal,  lateral,  and  ventral  views  of  a  typical  specimen,  enlarged  to  two 
diameters. 

TEREBRATULA  HASTATA 224 

Figs.  7,  7  a.  Dorsal  and  ventral  views  of  a  somewhat  crushed  specimen.    Natural  size. 
7  6.  Lateral  view  of  a  more  perfect  shell.     Natural  size. 

SPIRIFERA  DESIDERATA 217 

Fig.  8.  Dorsal  valve.    Natural  size. 


STATF.S  <;KOLOGICAL  SURVEY 


TA 1. 1. ONTOLOGY    Of    TIIK    IX'KKKA    DISTRICT       I'l..    VII 


CARBONIFEROUS 


PLATE    VIII. 

Page. 
PTERINOPECTEN  SPIO 233 

Fig.  1.     Loft  valve,  in  which  the  surface  has  been  largely  removed,  leaving  the  radiating 

costse  and  concentric  lines  in  strong  relief.     Natural  size, 
la.  Left  valve,  on  which  the  concentric  lines  are  faintly  defined.     Natural  size. 

MACRODON  TRUNCATUS 243 

Fig.  2.  Left  valve,  enlarged  to  nearly  three  diameters. 

PLEUROPHORUS  MEEKI 246 

Fig.  3.  Cast  of  left  valve.    Natural  size. 

STREBLOPTERIA  SIMILIS 230 

Fig.  4,  4  6.     Right  valves.    Natural  size. 
4  a,  4c.  Left  valves.    Natural  size. 
4d.  Finely  striated  left  valve.     See  plate  xix,  fig.  7. 

PTYCHOPTERIA  PROTOFORME 235 

Fig.  5.  Left  valve.     Natural  size. 

AVICULOPECTEN  PlXTflENSIS 228 

Fig.  C.  Left  valve.     Natural  size. 

CRENIPECTEN  HALLAXUS 231 

Fig.  7.      Cast  of  a  large  right  valve.     Natural  size. 
7  a.  A  small  right  valve. 
76.  A  large  left  valve.    Natural  size. 

7c.  Enlargement  of  the  surface  to  show  fine  concentric  striae  crossing  the  radiating 
plications. 

AVICULOPECTEN  PEROCCIDENS 227 

Fig.  8.  Left  valve.     Natural  size. 

PTERIXOPECTEN  HOOSACENSIS 232 

Fig.  9.  Left  valve.    Natural  size. 


fMTK.D    STATIS    GEOLOGICAL   SURVEY 


PALEONTOLOGY   OF  THE  EUREKA   DISTRICT      I'L.  VIII 


la 


id 


f 


?• 


=^V- 


CARBONIFEROUS 


PLATE    IX. 

Page. 

KUTORGINA  PROSPECTKNSIS 19 

Fig.  1.     Dorsal  valve,  enlarged  to  three  diameters, 
la.  Ventral  valve  equally  enlarged. 
1 6.  Restored  outline  of  the  two  valves  united. 

STENOTHECA  ELOKGATA 23 

Fig.  2.     Upper  side,  enlarged  to  three  diameters. 
2  a.  Lateral  view  of  the  same  specimen. 

LlNGULA?  MANTICULA 13 

Fig.  3.  Ventral  valve,  showing  the  more  ovate  form.    See  plate  xi,  fig.  2. 

KUTORGIXA  WHITFIELDI 18 

Fig.  4.     Ventral  valve,  with  outline  restored,  enlarged  to  two  diameters. 
4  a.  Dorsal  valve,  with  outline  of  convexity  below.    Natural  size. 

PROTOSPONGIA  FENESTRATA  Salter  f 11 

Figs.  5,5  a,  &.     Three  forms  of  spiculse;  56  is  the  more  unusual  form.    Natural  size. 

SCENEI.LA  T  CONICA 15 

Fig.  6.  Posterior  view,  showing  the  elevation ;  the  slight  groove  is  very  much  too  strong, 
it  is  scarcely  descernible  on  the  specimen. 

KUTORGINA  SCULPTILIS 20 

Fig.  7.  Dorsal  va've,  enlarged  to  six  diameters.     See  plate  i,  figs.  7. 7  a,  ft. 

ORTHIS  EUREKENSIS 22 

Fig.  8.     Dorsal  valve,  enlarged  to  three  diameters. 

80.  Ventral  valve,  similarly  enlarged  and  showing  the  cast  of  the  muscular  scars. 

ACROTRETA  GEMMA 17 

Fig.  9.     Lateral  view,  enlarged  to  four  diameters. 

9a.  View  from  above  of  the  same.     See  plate  i,  figs.  1  fl-e. 

AGNOSTUS  RICHMONDENSIS 24 

Fig.  10.  View  of  the  cephalic  shield,  enlarged  to  four  diameters. 

ACROTHELE  f  DICHOTOMA 14 

Fig.  11.  View  of  the  specimen  described,  enlarged  to  three  diameters. 

OLENELLUS  IDDIMGSI 28 

Fig.  12.  View  of  the  type  specimen,  enlarged  to  two  diameters. 

AGNOSTUS  BIDENS 26 

Fig.  13.     Cephalic  shield,  enlarged  to  four  diameters. 

13 a.  Small  caudal  shield  associated  with  the  above,  enlarged  to  five  diameters. 

AGNOSTUS  SECLUSUS ^ 

Fig.  14.  Cephalic  shield,  enlarged  to  four  diameters. 


PLATE  IX— Continued. 

OLENELLUS  HOWELLI 30 

Fig.  15.  View  of  a  specimen  fully  developed,  excepting  the  presence  of  an  ocular  ridge, 
and  the  distance  of  the  eyes  from  the  glabella.  The  genal  spines  are  too  short 
in  the  figure.  Natural  size. 

15 a.  Natural-size  view  of  a  head  -having  the  genal  angles  carried  forward;  eyes 
without  an  ocular  ridge,  and  the  angles  of  the  posterior  margin  strongly 
marked. 

15b.  The  head  of  a  young  individual,  enlarged  to  four  diameters,  in  which  the  embry- 
onic features  are  still  more  prominent.  See  plate  xxi,  figs.  1-9. 

15  c.  Fragments  of  thoracic  segments  associated  with  this  and  the  following  species. 

OLENELLUS  GILBERTI.. 29 

Fig.  16.     View  of  a  large  head,    Natural  size.     See  plate  xxi,  fig.  13. 

16  a.  Fragment  showing  the  glabella  and  a  portion  of  the  palpebral  lobes.    Natural  size. 

ANOMOCARE  ?  PARVUM 59 

Fig.  17.  Enlargement  of  the  specimen  described  to  five  diameters.  The  outline  of  the  pos- 
tero-lateral  limb  probably  extends  laterally  a  little  more  than  in  the  figure. 

PTYCHOPARIA  (?)  LINNARSSONI 47 

Fig.  18.     View  of  the  broad  form  of  the  head,  exclusive  of  the  free  cheeks,  X  2. 
18o.  View  of  the  narrow  form,  similarly  enlarged. 

DlCELLOCEPIIALUS  ?  EXPANSU8 45 

Fig.  19.  View  showing  the  character  of  the  glabella  and  the  peculiar  ridges  crossing  the 
anterior  portion  of  the  fixed  cheeks,  enlarged  to  one  and  one-half  diameters. 

PTYCHOPARIA  (?)  PROSPECTENSIS 46 

Fig.  20.  View  of  the  type  specimen,  enlarged  to  three  diameters.  The  furrow  crossing  the 
glabella  at  the  second  pair  of  glabellar  furrows  is  not  seen  in  the  specimen. 

PTYCHOPARIA  (PTEROCEPHALUS  ?)  OCCIDEXS 58 

Fig.  21.  The  test  is  largely  exfoliated  from  the  surface  of  the  glabella,  and  but  one  pair  of 
furrows  are  shown ;  figure  enlarged  to  three  diameters. 

OGYGIA.  ?  ?  SPINOSA 63 

Fig.  22.  View  showing  the  central  portions  of  the  head.    Natural  size. 

AGRAULOS  GLOBOSUS 61 

Fig.  23.  A  minute,  very  convex  head,  enlarged  to  four  diameters. 

DlCELLOCEPHALUS  ?  QUADRICEPS 45 

Fig.  24.  Small  head,  enlarged  to  three  diameters. 

DlCELLOCEPHALUS  OSCEOLA 40 

Fig.  25.  View  of  specimen  identified  with  the  Wisconsin  species.    Natural  size. 

PTYCHOPARIA  ANYTUS 56 

Fig.  26.  Central  portions  of  the  head,  enlarged  three  diameters.  The  fixed  cheeks  are  more 
elevated  at  the  outer  termination  of  the  ocular  ridges  than  represented. 

ARETHUSINA  AMERICANA 62 

Fig.  27.  View  of  central  portions  of  head ;  the  ocular  ridges  are  stronger  than  in  the  figure; 
enlarged  to  three  diameters. 

PTYCHOPARIA  (E. )  DISSIMILIS 51 

Fig.  28.  View  of  fragment  showing  the  central  portion  of  the  head.    Natural  size. 


U.  S.  Geolooical  Sin-rev 


PROSPECT   MOUNTAIN    GROUP. 


Geoloay  of  Eureka  District ,  Plate    IX 


16a 


., 


•  B  SimpscmBe] 


LATE    X 

Page. 
DlCELLOCEPIIALVS  ?  ANGUSTIFRONS 42 

Fig.  1.     View  of  the  movable  cheek  associated  with  the  glabella. 

1  a.  View  of  the  glabella,  palpebral  lobes,  and  outline  of  the  convexity  of  the  glabella. 

Natui-al  size. 
1&.  A  pygidium  occurring  in  the  same  hard  specimen  of  rock.    Natural  size. 

OGYGIA  t  PROBLEMATICA 63 

Fig.  2.     Usual  form  of  the  head  of  the  adult,  with  the  facial  sutures  and  outline  of  the  con- 
vexity of  the  glabella.    Natural  size. 

2  a.  Pygidium  associated  with  the  head  and  fragment  of  the  thoracic  pleura,  repre- 

sented by  fig.  2  &.     See  fig.  4. 

PTYCHOPARIA  OWENI 55 

Fig.  3.     Nearly  complete  head  within  the  facial  sutures,  enlarged  to  two  diameters. 
3 a.  Pygidium  associated  with  the  same,  similarly  enlarged. 

OGYGIA  ?  PROBLEMATICA 63 

Fig.  4.  Enlargement  to  four  diameters  of  a  small  head,  in  which  the  movable  cheeks  are 
absent,  the  postero-lateral  limbs  are  broken  away,  and  the  glabellar  furrows  obso- 
lete. There  are  specimens  intermediate  to  thos>:  represented  by  fig.  2  and  fig.  4. 

PTYCHOPARIA  OCCIDENTALIS 51 

Fig.  5.  View  natural  size,  showing  the  features  of  the  glabella  and  fixed  cheeks. 

DlCELLOCEPHALUS  RlCHMONDENSIS 41 

Fig.  7.  View  of  the  central  portions  of  the  head,  showing  the  broad  frontal  limb  and  fixed 
cheeks.  Natural  size. 

PTYCHOPARIA  ?  PERNASUTUS '. 49 

Fig.  8.     Upper  view  of  the  head  parts  discovered.    The  nasute  projection  of  the  frontal 

border  is  a  little  short  in  the  figure.    Natural  size. 
8 a.  Movable  cheek,  associated  with  the  preceding. 
8&.  Lateral  view  of  the  specimen  from  which  fig.  8  was  drawn. 

PTYCHOPARIA  (SOLENOPLEURA)  BREVICEPS 49 

Fig.  9.  View  of  the  type  specimen  to  show  the  broad,  short  form  of  the  head,  and  rounded 
conical  glabella,  enlarged  to  three  diameters. 

PTYCHOPARIA  (?)  SIMILIS 52 

Fig.  10.  Enlargement  to  two  diameters  of  the  central  portions  of  the  head,  showing  the  char- 
acter of  the  frontal  limb  and  glabella. 

PTYCHOPARIA - 00 

Fig.  11.  Movable  cheek,  associated  with  Plychoparia  nnisulcatus. 

PTYCHOPARIA  (E.)  AFFINIS 54 

Fig.  12.  View  of  specimen,  showing  the  narrow  frontal  limb,  as  compared  with  fig.  10,  and 
the  strongly-marked  glabellar  furrows,  enlarged  to  two  diameters. 


PLATE  X— Continued. 

Pago. 
DlCEIAOCEPHALUS  MARICA 44 

Fig.  13.  Enlargement  to  three  diameters  of  the  central  portions  of  the  head. 
Fig.  14.  Free  cheek,  associated  with  figs.  2  and  3. 

DlCELLOCEPHALUS  NASUTU8 40 

Fig.  15.  Central  portion  of  the  head,  showing  the  glabella  and  prolonged  anterior  border 
of  the  head.    Natural  size. 

CHARIOCEPHALUS  ?  TUMIFRONS 61 

Fig.  16.  Specimen  showing  the  frontal  margin,  and  a  less  protuberant  frontal  lobe  to  the 

glabella  than  in  the  type  of  the  species,  enlarged  to  two  diameters. 

Fig.  6.  Pygidium  associated  with  Chariocephalus  tumifrons,  and  supposed  to  belong  to  the 
species. 

PTYCHOPARIA  I^EVICEPS 64 

Fig.  17.  View  of  the  central  portions  of  the  head,  enlarged  to  three  diameters,  with  the  pos- 

tero-lateral  limbs  broken  off. 
18.  Free  cheek,  associated  with  the  heads  of  this  species  and  P.  Oweni. 

DlCELLOCEPHALUS  lOLE 43 

Fig.  19.  View  showing  the  strongly-marked  features  of  the  central  portion  of  the  head  of 

the  species,  enlarged  to  two  diameters. 
Fig.  20.  HYPOSTOMA,  associated  with  fragments  of  a  species  of  the  genus  Dicellocephalus, 

enlarged  to  three  diameters. 

PTYCHOPARIA •. 00 

Fig.  21.  Strongly  convex  hypostoma,  associated  with  Ptychoparia  Oweni,  enlarged  to  three 

diameters. 
Fig.  22.  An  hypostoma,  similarly  enlarged,  associated  with  Ptychoparia  any  i us,  P.  Oweni,  and 

P.  IcBviceps. 

PTYCHASPIS  MINUTA 60 

Fig.  23.  Enlargement  to  four  diameters  of  a  head,  showing  the  glabella,  fixed  cheeks,  ocu- 
lar ridges,  and  depressed  frontal  limb. 


Lr.  S.  Geological  Survey 


PROSPECT   MOUNTAIN    GROUP. 


Geology  of  Eureka  District ,  Plate  X. 


la 


2  a 


20 


22 


IB  Simpson Ilel 


T  Sinrlair  - 


PLATE    XI 

Page. 
TELUNOMYA  T  HAMBURGENSIS , 76 

Fig.  1.      Left  valve,  enlarged  to  two  diameters,  to  show  the  fine  surface  strise. 

la.  Same  valve,  showing  the  posterior  margin  more  depressed,  which  is  the  usual  form 
of  the  species,  enlarged  to  two  diameters. 

LlNGULAt  MANTICULA 13 

Fig.  2.      A  specimen  of  the  broad  variety  of  the  species,  from  which  the  outer  surface  is 
exfoliated,  enlarged  to  two  diameters.     See  plate  ix,  fig.  3. 

ORTHIS  PERVETA 72 

Figs.  3,  3 a,  36.  Dorsal,  ventral,  and  lateral  views  of  a  characteristic  specimen,  enlarged  to 
two  diameters. 

ORTHIS  TRICENARIA 74 

Figs.  4,  4  a.  Ventral  and  dorsal  views,  showing  the  strong  radiating  costse  and  form  of  the 
valves,  enlarged  to  two  diameters. 

ORTHIS  HAMBURGENSIS 73 

Fig.  5.      Ventral  valve,  enlarged  to  three  diameters  to  show  the  fissicostato  plications  and 

general  form  of  the  valve. 
5  a.  Same,  of  the  dorsal  valve. 

ORTHIS  LONENSIS 74 

Fig.  6     Ventral  view  and  outline  of  the  convexity  of  the  ventral  valve.     Natural  size. 
60.  View  of  the  area,  showing  the  triangular-shaped  foramen. 

TRIPLESIA  CALCIFERA 75 

Fig.  7.  Ventral  valve,  enlarged  to  two  diameters. 

8.  Ventral  valve  of  this  or  an  allied  species.    The  valve  is  convex  and  the  median  fold 
rounded. 

STREPTORHYNCHUS  MINOR 75 

Fig.  9.  Ventral  valve,  enlarged  to  two  diameters. 

ORTHIS  TESTUDINARIA 72 

Fig.  10.     Ventral  valve.    The  cardinal  angles  are  more  rounded  in  the  specimen. 
10 a.  Dorsal  valve  a  little  enlarged. 

RECEPTACUIITES  MAMMILLARIS 65 

Fig.  11.  View  looking  on  the  base  of  a  small  specimen. 

EECEPTACULITES  ELLIPTICUS 67 

Fig.  12.  Lateral  view. 

MODIOLOPSIS  POGONIPENSIS 78 

Fig.  13.  View  of  the  left  valve  enlarged  to  two  diameters.    See  plate  i,  fig.  6. 

MODIOLOPSIS  OCCIDENS 

Fig.  14.     Outline  of  a  large  right  valve,  as  seen  on  a  weathered  surface  of  rock. 

14  a.  Smaller  right  valve,  showing  the  exterior  form.    Natural  size.    See  plate  i,  fig.  5. 


PLATE  XI— Continued. 

Page. 
TELLINOMYA  CONTRACTA? 76 

Fig.  15.     Left  valve,  enlarged  to  two  diameters. 
15  a.  Interior  of  a  smaller  specimen. 

HYOLITHES  VANUXEMI 35 

Figs.  16,  16  a.  Views  of  the  ventral  and  dorsal  sides,  enlarged  to  two  diameters. 
166.  Transverse  section  of  the  tube. 

COLEOPRION  MINUTA 85 

Figs.  17,  17  c.  Lateral  views  of  a  straight  and  slightly  curved  tube,  enlarged  to  four  diam- 
eters.   See  plate  xii,  fig.  21. 

MACLUREA  SUBANNULATA 82 

Fig.  18.      View  of  the  upper  side,  showing  the  depressed  character  of  the  spire  and  the  an- 

nulations  on  the  cast  of  the  outer  whorl. 
18  a.  View  of  the  lower  side  of  the  same  specimen. 

18  b.  Section  of  the  outer  whorl. 

MACLUREA  ANNULATA 81 

Fig.  19.     View  of  the  lower  side,  showing  the  annulations  of  the  outer  surface  of  the  shell, 
enlarged  to  two  diameters. 

19  a.  Internal  cast  of  the  lower  side,  similarly  enlarged. 

MACLDREA  CARINATA 82 

Fig.  20.     View  of  the  lower  side,  showing  the  strong  surface  striae. 

20  a.  Cast  of  the  lower  side. 

RAPHISTOMA  NASONI 78 

Figs.  21,  21  a.  Lateral  and  summit  view  of  small  specimen. 

PLEUROTOMARIA  LONENSIS 80 

Fig.  22.  Lateral  view  of  the  specimen  from  Lone  Mountain.    Natural  size. 


i  lurra  u 

POGONIP    GROUP. 


I    S.  Geological  Survey 


Geoloay  oT  Kureka  "District, -I'hitc    XI 


4a 


L( 


16TD 


18  a 


18 'b 


21a 


19  a 


3a 


10  a 


17a 


16a 


20 


5a 


15  a 


22 


G-B.  SampsonBe] 


PLATE    XII. 

Page. 

ENDOCERAS  PROTEIFORME 86 

Fig.  1.     View  of  siphuncle  with  included  tube. 
la.  Cross-section  of  another  specimen. 
1  c.  Opposite  side  of  upper  portion  of  fig.  1,  showing  annulated  shell  of  the  siphuncle. 

ORTHOCERAS,  sp.  T 87 

Fig.  1  b.  Oblique,  transverse  section.  The  outer  shell  is  restored  and  is  too  small,  and  it  is 
also  less  circular  in  outline.  The  fragment  crossing  the  siphuncle  is  of  acci- 
dental origin. 

ORTHOCERAS,  sp.  ? 86 

Fig.  2.  A  portion  of  the  shell,  preserving  a  number  of  the  septa  and  a  portion  of  the 
siphunclo. 

ORTHOCERAS  MULTICAMERATUM  f 86 

Fig.  3.  Fragment  showing  the  form  of  the  tube,  the  septa,  and  a  portion  of  the  siphuncle. 

ILL^NURUS  EUREKENSIS !W 

Fig.  4.      View  of  the  central  portion  of  the  head  and  outline  of  the  convexity  of  the  same, 

enlarged  to  two  diameters. 
4  a.  Associated  free  cheek. 

BARRANDIA!  McCovi 96 

Fig.  5.  View  of  the  glabella  and  fixed  cheeks,  and  a  longitudinal  outline  of  the  convexity 
of  the  head,  enlarged  to  two  diameters. 

BARRANDIA  f  sp.  T 96 

Fig.  6.  View  of  the  glabella.    Natural  size. 

ASAPHUS  CARIBOUENSIS 98 

Fig.  7.     View  of  the  head  within  the  facial  sutures,  also  outline  of  longitudinal  section. 
7  a.  An  associated  free  cheek. 

7  6.  Pygidium  found  in  the  same  association. 

BATHYURUSf  CONGENERIS - 92 

Fig.  8.     View  of  glabella  and  fixed  cheeks,  enlarged  to  two  diameters. 

8  a.  Pygidium  associated  in  the  same  layer  of  rock. 

BATHYURUS  TUBERCULATUS 

Fig.  9.  View  of  the  glabella  and  a  portion  of  the  fixed  cheeks,  enlarged  to  two  diameters. 

CYPHASPIS?  BREVIMARGINATA 

Fig.  10.  Enlargement  to  three  diameters  of  the  only  specimen  discovered. 

BATHYURUS  f  SIMILLIMUS - 

Fig.  11.  Enlargement  to  three  diameters,  to  show  the  character  of  the  glabella  and  frontal 
margin. 


PLATE  XII— Continued. 

Paga 
DlCELLOCEPHALUS  FINALI8 -.  89 

Fig.  12.     View  of  the  central  portions  of  the  head.    Natural  size. 
12 a.  Associated  pygidium,  enlarged  to  two  diameters. 
22.     Portion  of  a  thoracic  segment  on  the  same  fragment  of  rock. 

AMPHION  NEVADENSIS 94 

Fig.  13.  View  of  the  portions  of  the  head  preserved  in  the  type  specime.    Natural  size. 
14.  Pygidium  of  unknown  generic  and  specific  relations,  occurring  in  association  witi. 
Asaphus  Caribouensis,  enlarged  to  three  diameters. 

ASAPHUS  ?  CUBIOSUS  I 98 

Fig.  15.  Pygidium  associated  with  Asaphus  Caribouensis,  enlarged  to  two  diameters. 

SYMPHYSTJRUS  f  GOLDFUSSI 95 

Fig.  16.  View  of  the  glabella  and  portions  of  the  fixed  cheeks,  enlarged  to  two  diameters. 

CERAURUS  ? 95 

Fig.  17.  Glabella  enlarged  to  three  diameters,  to  show  the  granulose  surface. 

PTYCHOPARIA  (?)  ANNECTANS 91 

Fig.  18.  Glabella  and  fixed  cheeks,  enlarged  to  two  diameters. 

AMPYX  ? 00 

Fig.  19.  Pygidinm  associated  with  the  preceding,  and  also  figs.  7  and  12,  enlarged  to  two 
diameters. 

ASAPHUS 00 

Fig.  20.  Strongly  convex  pygidium,  associated  with  Asaphus  Caribouetisis. 

COLEOPRION  MINUTA-- 85 

Fig.  21.  Enlargement  of  a  portion  of  the  tube  to  four  diameters,  to  show  the  arching  of 
the  striae  over  the  longitudinal  ridge  on  the  side  opposite  the  arc  of  curvature. 
See  plate  xi,  figs.  17,  17  a. 


T,T.  S.  Geological  Sui-vey. 


POGONIP     GROUP. 


Geology  of  Eureka  District ,  Plate  X II 


T  Sir.clair  fc  Son, Li 


\ 


PLATE    XIII. 

Page. 
LlNGULA  LONENSiS 108 

Fig.  1.     Ventral  f  valve. 

1  a.  Dorsal  ?  valve.    Natural  size. 

LlNGULA  LuENA 106 

Fig.  2.  Ventral  valve,  from  which  the  surface  is  largely  exfoliated.    Natural  size. 

LINGULA  WHITKI 109 

Fig.  3.  Cast  of  the  interior  of  the  dorsal  valve,  enlarged  to  two  diameters. 

d.  Divaricator  muscular  scar, 
ad.  Adjuster  muscular  scars. 
p  o.  Posterior  adductor  scar. 
a  a.  Anterior  adductor  scar. 

pp.  Supposed  area  of  attachment  of  the  posterior  parietal  muscle. 
M  M.  Supposed  area  of  attachment  of  the  walls  of  the  peri  visceral  cavity. 
p  8.  Great  pallia!  sinus. 
1 8.  Lateral  branches  of  the  great  sinus. 

t.  Area,  that  in  another  specimen  shows  the  inner  ramifications  of  the  great  sinus. 
The  various  features  are  rather  strongly  shown  in  the  figure,  but  not  more 
so  than  is  justified  by  the  original  specimen. 

SKENIDIUM  DEVONICUM 116 

Fig.  4.     Ventral  valve,  enlarged  to  three  diameters. 

4  a.  Cardinal  view,  showing  the  areas  of  the  two  valves,  the  foramen,  and  the  medium 
septum  of  the  dorsal  valve. 

DlSCINA  MINUTA '. '. 112 

Fig.  5.  View  of  a  rather  elongate  dorsal  valve,  enlarged  to  two  diameters. 

STROPHODONTA  CALVINI 122 

Fig.  6.  View  of  ventral  valve.    Natural  size. 

STREPTORHYNCHUS  CHEMUNGENSIS 117 

Fig.  7.     View  of  a  specimen  referred  to  the  variety  arctostriata.    Natural  size. 

16.  View  of  a  specimen  corresponding  to  the  typical  forms  of  the  species.  Natural  size. 

PRODUCTUS  SPECIOSUS 133 

Fig.  8.  View  showing  the  surface  ornamentation  and  form  of  the  ventral  valve.    Natural 
size. 

PRODUCTUS  NAVICELLUS 131 

Fig.  9.  Lateral  view  of  a  somewhat  strongly  costate  variety,  enlarged  to  tfro  diameters. 

STROPHODONTA  PUNCTULIFERA 121 

Fig.  10.  View  of  ventral  valve,  showing  radiating  striae  and  punctate  surface.    Natural 
size. 

STROPHODONTA  PERPLANA 120 

Fig.  11.  View  of  a  well-preserved  ventral  valve,  with  a  portion  of  the  outer  surface  exfoli- 
ated. 


PLATE  XIII— Continued. 

Page. 
PAL^OMANON  ROEMERI 

Fig.  12.  View  showing  the  cup-shaped  summit  and  general  form.    Owing  to  silicification, 
the  details  of  the  structure  are  destroyed. 

ORTHJS  IMPRESSA 115 

Fig.  13.  Cast  of  ventral  valve.    Natural  size. 

CHONETES  MACROSTRIATA 126 

Fig.  14.     Ventral  view  and  outline  of  the  convexity  of  an  average  size  specimen. 

14  a.  Same  view  of  an  unusually  large  specimen  from  which  the  striated  outer  surface 

has  been  removed,  showing  the  inner  punctate  surface. 
146.  View  of  ventral  valve  of  a  small,  strongly-marked  specimen,  to  which  a  cardinal 

spine  is  attached;  14, 14  a,  &  are  natural  size. 

14  c.  Enlargement  of  the  striae  of  fig.  14,  to  show  manner  of  bifurcation.     See  plate  ii, 

fig.  13. 

CHONETES  FILISTRIATA 127 

Fig.  15.     Ventral  view  of  average  size  specimen,  showing  surface  striae  and  cardinal  spines. 

15  «.  Enlargement  of  the  area  of  the  ventral  valve,  showing  the  shape  of  the  foramen. 

PBODUCTUS  HALLANUS 130 

Fig.  17, 17  a.  Dorsal  and  ventral  view  of  average  size  specimens. 

PRODUCTUS  LACHRYMOSUS,  var.  LIMUS 132 

Figs.  18,  18 a.  Lateral  and  front  view  of  the  ventral  valve. 

PRODUCTUS  SUBACULEATUS 128 

Figs.  19, 19  a.  Ventral  and  cardinal  views  of  a  specimen  from  which  the  outer  shell  is  par- 
tially exfoliated. 

20,20o.  Same  view  of  the  type  of  the  species  copied  from  plate  ii,  tome  xi,  Bull,  Soc. 
Geol.  de  France.  The  spine  bases  are  stronger  than  in  19, 19 a,  but  in  other  speci- 
mens they  are  much  as  in  figs.  20, 20  a.  See  plate  vii,  fig.  2. 


I.    S    Geological  Sui-vey 


Geology  of  Eureka  District ,  Halt-  Xlll 


15a 


14b 


15 


17  a 


18 


I  J 


18  a 


14  c 


20 


19  a 


20a 


G  B  Simpson  Del 


PLATE    XIV. 

Page. 

PRODUCTUS  SHUMARDIANUS.... 129 

Fig.  1.  View  of  the  dorsal  valve.    Natural  size. 

PRODUCTUS  TRUNCATUS 

Fig.  2.  View  to  show  the  truncated  apex  of  the  ventral  valve.     Natural  size. 

RHYNCHONELLA  HORSFORDI 152 

Fig.  3.  Ventral  view  of  an  average  size  specimen.    See  plate  xv,  fig.  6. 

ATRYPA  DESQUAMATA 150 

Fig.  4.     View  of  the  ventral  valve. 

4  a.  Cardinal  view  to  show  the  small  area.    Natural  size. 

RHYNCHONELLA  (L.)  SINUATA 158 

Fig.  5.  Dorsal  view  of  a  characteristic  specimen.     Natural  size. 

ATRYPA  RETICULARIS l-r>0 

Figs.  6, 6 a,  6 ft.  Ventral,  lateral,  and  dorsal  views  of  the  small  variety  mentioned  in  the  text 
as  characteristic  of  the  Niagara  formation. 

RHYNCHONELLA  PUGNUS „ 155 

Figs.  7,7 a.    Lateral  and  ventral  views  of  an  average  size  specimen. 

RHYNCHONELLA  DUPLICATA 155 

Fig.  8.  Dorsal  view  of  a  very  striking  example  of  the  species. 

RHYNCHONELLA  (L.)  NEVADENSIS 157 

Figs.  9,9  a,  9fc.  Ventral,  lateral,  and  dorsal  views  of  the  ordinary  type  of  the  species. 

SPIRIFERA  PARRYANA 137 

Fig.  10.  Ventral  view  of  the  only  specimen  obtained,  showing  the  costse  and  fine  radiating 
striae. 

SPIRIFERA  (M.)  UNDIFERA 143 

Figs.  11, 11  a,  ft.  Dorsal,  lateral,  and  ventral  views  of  a  specimen  from  which  most  of  the 

outer  surface  is  removed. 
136.  Ventral  valve  with  a  portion  broken  away,  showing  the  cast  of  the  muscular 

impression. 
13  c.  Ventral  valve  of  a  broad  variety  of  the  species,  showing  the  area  and  small  del- 

tidium  in  place.     See  plate  iii,  figs.  3,  3  a,  b,  6,  6  a. 

SPIRIFERA  (M.)  RARICOSTA 135 

Fig.  12.  View  of  the  partial  cast  of  the  dorsal  valve  of  a  small  shell.    See  plate  iv,  figs.  2, 2  a. 

SPIRIFERA(M.)MAIA 141 

Figs.  13, 13  a.  Dorsal  and  lateral  views  of  an  average  specimen  of  the  species.     See  plate 
iii,  figs.  1,  1  a-e. 

SPIRIFERA  (M. )  GLABRA,  var.  NEVADENSIS 139 

Figs.  14, 14  a,  6.  Dorsal,  lateral,  and  front  views  of  the  largest  and  most  transverse  speci- 
men in  the  collection.     See  plate  iii,  fig.  5. 

PKNTAMERUS  (M.)  COMIS 159 

Figs.  15,  5  a,  1).  Dorsal,  lateral,  and  ventral  views  of  a  transverse,  smooth  specimen.    See 
plate  iii,  figs.  4,  7,  and  plate  xv,  figs.  5, 5o,  c. 


1.'.  S.  Geological  SUI-VPY. 


Geology  of  Eureka  District,  HatcX'.V 


LO 


15 


6a 


9  a 


15a 


4a 


15b 


7a 


,  2 


13  c 


G  B  SinrpstraDel 


PLATE    XV. 

Page. 
RHYNCHONELLA  CASTANEA 153 

Figs.  1, 1  a.  Front  and  lateral  views  of  a  small  subcuboidal  specimen. 
4,  4  o.  Ventral  and  lateral  view  of  an  adult  shell. 

CRYPTONELLA  ?  CIRCULA 163 

Figs,  2,  2  a,  6.  Ventral,  lateral,  and  dorsal  views  of  a  rather  large  specimen,  enlarged  to 
two  diameters. 

RHYNCHONELLA  ?  OCCIDENS 152 

Figs.  3. 3  a,  Z>.  Dorsal,  ventral,  and  lateral  views  of  a  typical  specimen,  enlarged  to  two 
diameters. 

PENTAMERUS  COMIS 159 

Figs.  5.        Ventral  view  of  a  specimen,  showing  obscure  plications  towards  the  front. 

5  a,  5  b.  Lateral  and  ventral  views  of  a  rotund,  smooth  example.     See  plate  iii,  figs.  4 
and  7,  and  plate  xiv,  figs.  15,  15  a,  ft. 

RHYNCHONELLA  HORSFORDI 15a 

Fig.  6.  Dorsal  view  of  a  little  smaller  example  than  that  shown  by  fig.  3,  plate  xiv. 

ANADONTOPSIS  AMYGDAKEFORMIS 180 

Fig.  7.      Lateral  view  of  the  left  valve. 

7  a.  Cardinal  view  of  the  two  valves  united. 
7  6.   Anterior  view  of  the  same. 

« 
DYSTACTELLA  INSULARIS 172 

Fig.  8.  Lateral  view  of  the  left  valve,  showing  the  anterior  muscular  scar. 

NUCULA  RESCUENSIS 172 

Fig.  9.  .View  of  left  valve,  enlarged  to  three  diameters. 

GONIOPHORA  PERANGULATA t 171 

Fig.  10.  View  of  left  valve,  showing  the  strongly-marked  angular  ridge. 

C YPRICARDINIA  INDENTA 182 

Fig.  11.  Lateral  view  of  left  valve,  enlarged  to  two  diameters,  to  show  the  characteristic 
surface  markings.    See  plate  v,  fig.  14. 

PTERINEA  FLABELLA 165 

Fig.  12.  Example  from  Lone  Mountain.     See  plate  v,  fig.  6. 

SANGUINOLITES  VENTRICOSUS 177 

Fig.  13.  View  of  left  valve  of  a  specimen  preserving  the  characters  of  the  species. 

NYASSA  PARVA 173 

Fig.  14.     View  of  right  valve,  showing  the  muscular  impressions,  enlarged  to  three  diam- 
eters. 
14  o.  Left  valve,  similarly  enlarged. 

GRAMMYSIA  MINOR 174 

Figs.  15,  15  a.  View  of  right  and  left  valves,  enlarged  to  two  diameters. 

SANGUINOLITES  COMBENSIS 175 

Fig.  16.  View  of  right  valve.     Natural  size. 


~U.  8.  Geological  Sui-ve'v: 


Geology  of  Eureka  District.  Plntt;  XV 


2a 


2  b 


la 


4a 


7b 


16 


PLATE    XVI. 

PLATYCERAS  CONRADI 182 

Fig.  1.    .Lateral  view,  showing  the  first  volution  and  the  sinuosity  of  the  peristome. 

1  a.  Dorsal  views  of  another  example,  showing  the  concentric  ridges  on  tho  back. 

EUOMPHALUS  EUREKENSIS 185 

Fig.  2.     Cast  of  a  medium  size  shell. 

2  a.  Lateral  view  of  the  cast  of  a  large  shell,  showing  the  sinuosity  in  tlie  aperture 

and  the  decollation  of  the  inner  whorls. 

CALLONEMA  OCCIDENTALIS 189 

Fig.  3.      Lateral  view,  showing  the  depressed  spine. 

3  a.  Vertical  view.     The  lines  on  the  left  side  are  an  accidental  feature. 

CONOCARDIUM  NEVADENSI8 177 

Figs.  4,  4  a.  Two  views,  showing  the  character  of  the  species. 

LEPERDITIA  ROTUNDATA 206 

Fig.  5.  Enlargement  to  four  diameters  of  the  right  valve. 

SANGUINOLITES  RIGIDUS 176 

Fig.  0.  Left  valve.     Natural  size. 

STRAP AROLLUS  NEWARKENSIS 187 

Fig.  7.      Basal  view.  ^ 

7  a.  Summit  view  of  same  specimen,  enlarged  to  two  diameters. 

LOXONEMA  EUREKENSIS 190 

Fig.  8.  View  of  internal  cast. 

LOXONEMA  NOBtLE , 190 

Fig.  9.  View  of  internal  cast. 


i:.  S.  Goolooicttl  SUI-VCY. 


(iroloay  of  Enrok/t  nistrirt.  Plate  JYT 


GB  SunpsonDe] 


PLATE    XVII. 

Page. 
PLATYSCHISMA  McdOYi 188 

Figs.  I,  ia,  1  b.  Summit,  lateral,  and  basal  view  of  a  small  specimen.     Natural  size. 
Ic.  Longitudinal  section  of  a  larger  shell. 

METOPTOMA  ?  DEVONICA 195 

Figs.  2, 2  a.  Lateral  and  anterior  view  of  the  type  specimen. 

PLATYSCHISMA  ?  AMBIGUUM 

Figs.  3,  3 a.  Lateral  and  summit  view  of  a  silicified  specimen. 

BEYRICHIA  (P)  OCCIDENTALIS JU 1 

Fig.  4.     Large  size  left  valve,  enlarged  to  four  diameters 

4a.  Enlargement  of  a  young  specimen  (lmm)  in  length,  to  show  the  unisulcate  char- 
acter at  this  stage  of  growth,  x  12. 

DALMANITES  MEEKI 

Fig.  5.  View  of  the  glabella  of  a  medium  size  specimen. 

5 a,  5ft.  Dorsal  and  lateral  views  of  a  medium-size  and  large  pygidium. 
5c.         Enlargement  of  a  portion  of  the  surface  of  56,  to  show  the  punctate  chara- 
of  the  test. 

BELLEROPHON  PERPLEXA 193 

Fig.  6.     Transverse  section,  showing  the  deep,  open  umbilicus  and  flattened  whorls. 
Qa.  Dorsal  view,  showing  the,dorsal  ridge  and  the  direction  of  the  strhe. 
G 1).  Longitudinal  section,  showing  the  closely  coiled  whorls. 

C YRTOCERAS  NfiVADENSIS • 20'.\ 

Fig.  7.     Lateral  view,  showing  the  depth  of  the  chambers  and  the  curvature  of  the  tube. 
7 a.  Ventral  view  of  the  same,  with  the  surface  stria3  preserved. 

GOMPHOCERAS  SUBOVIFORME -Ji  i-j 

Fig.  8.     Ventral  view,  showing  the  chamber  of  habitation,  air-chambers,  and  a  portion  of 

the  siphuncle  exposed  by  the  weathering  of  the  specimen. 
8  a.  Lateral  view  of  the  Fame. 

BELLEROPHON  COMBBI 193 

Figs.  9, 9a.  Lateral  and  front  view,  to  show  the  form  of  the  species. 

GOMAIITES  DESIDERATUS -J03 

Fig.  10.  Lateral  view  of  a  specimen  preserving  a  portion  of  the  surface  striro  on  the  inner 
volution. 


IT.  S.  Geological  Survey. 


Geolojgy  of  Eiireka  District,  Plaie  XVH 


la 


GB  Sampson  Del 


PLATE    XVIII. 

Pane. 
LlNGULA  MYTILOIDES  ?  .............................................  279 

Fig.  1.  View  of  a  specimen  from  the  lower  portion  of  the  Carboniferous  formation,  north  of 
Pinto  Peak. 

DISCIXA  NEWBERRYI  ..........................................  213 

Figs.  2,  2«.  Dorsal  and  ventral  valves  of  a  form  from  the  shale  in  Secret-canou-road  Canon, 
doubtfully  referred  to  this  species,  enlarged  to  two  diameters. 
Dorsal  valve  from  Richmond  Mountain.     Natural  size. 


SPIRIFERA  LEIDYI 


Figs.  4,  4  a.  Dorsal  and  ventral  views  of  the  average  size  specimens  found  at  Richmond 
Mountain. 

ATHYKIS  HIKSUTA  .....................  *  ....................................................          222 

Fig.  •").  Dorsal  view  of  a  specimen  from  Coal  Hill,  Pancake  Mountains.  White  Pine  County, 
Nevada. 

CAM  AROPHORIA  COOPERENSIS   ..............................................................  ->>4 

Fig.  6.  Ventral  view  of  a  specimen  from  Richmond  Mountain. 

SPIRIFERA  ANNECTANS  ......................................................................          216 

Figs.  7,  7a.  Dorsal  and  ventral  views,  showing  the  rounded  cardinal  extremities,  and  the 
coarse  plications. 

RHYNCHONELLA  EUREKENSIS  ...............................................................          223 

Fig.  8.         Lateral  view  of  a  specimen  which  is  slightly  crushed. 
Sa.      Ventral  view  of  the  same. 

8  b,  c.  Ventral  and  dorsal  views  of  a  smaller  example. 

ATHYRIS  ROYSSII  ...........................................................................         280 

Fig.  9.     Dorsal  view  of  a  specimen  from  the  canon  north  of  Pinto  Peak. 

9  a.  Lateral  view  of  the  same. 

SPIRIFERA  NEGLECTA  .......................................................................          217 

Fig.  10.  View  of  a  ventral  valve,  from  Richmond  Mountain. 

SPIRIKERA  TRIGONALIS  ...^  .................................................................         215 

Fig.  11.  View  of  a  ventral  valve,  from  which  the  outer  shell  is  largely  removed. 

SPIRIFERINA  CRISTATA  ......................................................................          218 

Fig.  12.  Dorsal  view  of  a  specimen  from  the  Chester  limestone  of  Chester,  111.     Introduced 

for  comparison. 

13.  Same  view  of  a  specimen  from  the  upper  portion  of  the  Carboniferous  Group  in  the 
Eureka  District.  The  spine  bases  are  not  shown  in  the  figures,  although  quite 
prominent  on  the  shells  from  each  locality. 

STREPTORHYNCHTJS  CRENISTRIA  .............................................................         279 

Fig.  14.  View  of  a  strongly  striate  form,  found  at  Richmond  Mountain. 


PLATE  XVIII— Continued. 


PLEUROTOMARIA  NODOMARGINATA 

Fig.  15.  Enlargement  to  three  diameters  of  a  typical  specimen,  from  the  lower  portion  of  the 
Carboniferous  Group. 

METOPTOMA  PEROCCIDENS 

Fig.  16.  Summit  view,  showing  the  outline  and  the  radiating  dark  lines  and  fine  concentric 
striae. 


ORTHOCERAS  RANDOLPHENSIS  ? 

Fig.  17.  View  of  a  crushed  fragment  of  the  tube. 

BELLEROPHON  TEXTILIS 

Ffg.  18.  View  of  broken  specimen,  showing  the  surface  characters  and  general  form. 

EUOMPHALUS(S.)  SUBRUGOSU8 

Fig.  19.  Summit  view  of  a  small  characteristic  specimen. 


Page. 
259 


260 

265 
257 
255 


IT.  S.  Geological  Survey: 


Geology  of  Eureka  District.  Plate  XVIII. 


7  a 


PLATE    XIX. 

Page. 
A  VICULOPECTEN  AFFINIS 229 

Fig.  1.      Left  valve  of  an  average  size  specimen. 

la.  Right  valve  of  a  smaller  shell,  in  which  the  sinus  is  deeper  beneath  the  anterior  ear. 

A  VICULOPECTEN   EUREKENSIS '--' 

Fig.  2.  View  of  a  left  valve  compressed  laterally. 

3.  Left  valve  with  the  anterior  ear  restored  in  outline.    Shell  flattened  by  compression. 

AVICULOPECTEN   HAGUEI 

Fig.  4.  Left  valve  with  the  outline  of  the  posterior  basal  margin  restored  from  the  matrix, 
the  margin  of  the  shell  having  been  broken  away. 

MYALIXA  NEMESIS •-':'>? 

Fig.  o.  Left  Aralve  with  the  beak  broken  away.     See  plate  xxii,  tig.  7. 
MYALIXA  CONGENERIS 

Fig.  6.  View  of  the  smallest  left  valve  collected.     It  is  about  three-fourths  of  rue  size  of 
the  largest  specimen.    See  plate  xxii,  fig.  10. 

STREBLOPTERIA  SIMILIS 230 

Fig.  7.  Right  valve.     See  plate  viii,  figs.  4,  4o-d. 

MODIOLA  ?  NEVADENSIS 239 

Fig.  8.  View  of  a  somewhat  compressed  specimen  of  the  right  valve. 

SANGUIXOLITES  ?  N^NIA 249 

Fig.  it.  Right  valve. 

PTERIXEA  PINTOENSIS 234 

Fig.  10.  View  of  left  valve,  enlarged  to  two  diameters. 

PINNA  INEXPECTANS 235 

Fig.  11.  View  of  posterior  half  of  left  valve. 


II.  S.  Geological  Survev. 


Geology  of1  Eureka  District.  Plate  XIX 


^^"SSfcpr— 


la 


w 

* 


P1L.ATE    XX. 

Page. 

MODIOMORPHA  AMBIGUA 239 

Fig.  1.  Left  valve  of  a  slightly-crushed  specimen. 

MODIOMORPHA  *  PINTOENSIS 240 

Fig.  2.  View  of  the  specimen  used  in  the  description. 

MODIOMORPHA?  DESIDERATA —         240 

Fig.  3.  Anterior  portions  of  the  right  and  left  valves,  as  they  appear  on  a  fragment  of  lime- 
stone. 

GRAMMYSIA  HANNIBALENSIS 244 

Fig.  4.  View  of  a  right  valve  which  is  a  little  compressed. 

GRAMMYSIA  ARCUATA 24& 

Fig.  5.  Right  valve  found  in  the  same  beds  -with  the  preceding  species. 

SANGUINOLITKS  AEOLUS 247 

Fig.  6.      Elongate  form  of  right  valve,  very  closely  allied  to  the  type  examples  of  the  species. 
7, 9.  Right  and  left  valves  of  two  sheila  that  vary  in  form  from  fig.  6. 

SCHIZODUS  CUNEATUS 232 

Fig.  8.  View  of  the  right  valve. 

SANGUINOLITES  RETUSUS 247 

Fig.  10.  Right  valve.    The  radiating  ridges  of  the  umbonal  slope  are  too  strong  in  the  figure. 

SANGUINOLITES  SIMPLEX 24S 

Fig.  11.  View  of  the  right  valve. 

SANGUINOLITES  SALTERI 24S 

Fig.  12.  Right  valve  showing  the  strong  radiating  lines  of  the  umbonal  slope. 

PINNA  CONSIMILIS 236 

Fig.  13.  View  of  a  small  specimen  of  the  left  valve,  with  portions  restored  in  outline. 

VUCULA  INSULARIS 241 

Fig.  14.  Left  valve,  showing  general  form  and  the  tine,  concentric  surface  strite. 


IT.  S.  Geological  Survey: 


Geology  of  Eureka  District.  Plate  XX 


10 


H 


G.B.  Simpson  Del 


PLATE    XXI. 

Page. 
OLENBLLUS  HOWELLI 30 

Fig.  1.  Outline  of  the  smallest  head  of  this  species  discovered.    Natural  size. 

2.  Head  showing  the  anterior  position  of  the  genal  spines,  g  g,  and  the  angles  of  the 

posterior  margin,  xx,  extravagantly  developed.  The  difference  in  the  length  of 
the  ocular  ridges  of  the  right  and  left  side  is  also  very  marked.  Natural  size. 

3.  The  smallest  individual  in  which  the  posterior  course  of  the  facial  suture  was 

observed.     The  outline  of  the  head  is  much  like  that  of  fig.  1.    Natural  size. 

4.  Form  intermediate  in  contour  of  head,  between  figs.  2  and  3.    g  g,  Genal  angles 

and  spines;  xx,  angles  of  the  posterior  margin.    Natural  size. 

6.  The  eyes  in  this  specimen  are  no  longer  peduuculated  or  united  to  the  glabella  by 
an  ocular  ridge,  and  the  genal  angles  are  more  posterior.  The  course  of  the 
facial  suture  in  front  of  the  eye  is  also  seen  for  the  fir»t  time.  Natural  size. 

6.  Example  in  which  the  genal  angles  are  in  the  same  position  as  in  the  adult  indi- 

vidual in  species  of  the  genus.  The  eyes  are  more  embryonic  in  character  than 
in  the  preceding  example.  Natural  size. 

7.  Narrow  form,  with  the  eyes  of  the  adult  type,  and  having  the  genal  angles  carried 

forward,  as  in  the  younger  individuals,  1,  3,  5.    Natural  size. 

8.  Broader  and  more  common  form  showing  the  same  peculiarities  as  fig.  7.    Natural 

size. 

9.  The  right  and  left  sides  are  irregularly  developed,  the  genal  spine  on  the  left  side 

being  more  anterior  in  position.  The  course  of  the  facial  suture  is  traced  in 
accordance  with  its  position,  as  observed  in  fig.  6.  Natural  size. 

OLENBLLUS  ASAPHOIDES  Emmons 36 

Fig.  10.  Embryonic  form,  showing  the  circular  outline,  the  genal  spines  in  close  proximity 
to  the  facial  suture,  and  the  interocular  spines.  Enlarged  to  3.5  diameters. 
(After  Ford.) 

11.  Another  phase  of  the  development  of  this  species,  succeeding,  with  probably  in- 

termediate forms,  fig.  10.  The  posterior  of  the  genal  spines,  g  g,  and  the  sutures 
cutting  the  posterior  margin  at  the  angles,  x  x,  are  comparable  to  the  same  in  fig.  3. 
Enlarged  to  five  diameters.  (After  Ford.) 

12.  Normal  adult  type  of*head  of  this  species,  enlarged  to  two  diameters.    (After  Ford.) 

OLENELLUS  GILBERT: -.29 

Fig.  13.  Small  head,  natural  size,  for  comparison  with  figs.  2,  3,  etc.,  of  its  associate  species, 

0.  Howdli,    A  large  head  is  figured  on  plate  ix,  fig.  16. 

14.  Narrow  form  of  head,  that  shows  the  angles  in  the  posterior  margin,  xx,  slightly 
developed.  Natural  size.  (After  White.) 

PARADOXIDES  KJERULFI  Linnarsson 39 

Fig.  15.  Outline  of  head  showing  the  position  of  the  genal  angles  and  angles  of  the  pos- 
terior margin,  xx,  with  the  interocular  spine;  also  the  ocular  ridge  (c)  uniting 
the  glabella  and  eyes.  (After  Linnarsson.) 

OLBNELLUS  HOWELLI 30 

16.  Outline  of  hypostoma  found  associated  with  this  species.    Enlarged  to  three  diam- 

eters. 

17.  Free  cheek  found  detached  from  the  fixed  chdfek.    The  direction  of  the  suture  in 

front  of  the  eye  is  well  definedf,  «;  its  direction  posteriorly  may  be  along  the  line 
of  fracture,  o  o,  but  it  is  impossible  to  satisfactorily  determine  it.  If,  as  in  fig.  6, 
it  would  followthe  dotted  line,  o  x. 


PLATE  XXI— Continued. 

Page. 
LINGULA  ELDERI Ill 

Fig.  18.  Outline  of  the  interior  of  the  dorsal  valve,  showing  the  muscular  and  vascular 
markings: 

d.  Divaricator  muscular  scar. 
a  d.  Adjuster  muscular  scars. 
p  a.  Posterior  addiictor  scars. 
a  a.  Anterior  adductor  scars. 
xx.  Track  of  advance  of  the  muscular  scars. 

s.  Great  pallial  sinuses. 
p  s.  Posterior  course  of  the  latter. 
o.  Inner  ramifications  of  the  sinuses. 
(After  Whitfield.) 

LINGULA.  WHITEI 109 

Fig.  19.  Outline  of  the  figure  of  this  species  on  plate  xiii,  fig.  5.    The  corresponding  parts 
are  lettered,  as  in  fig.  18. 

LINGULA  AFFINIS Ill 

Fig.  20.  Dorsal  valve,  reduced,  after  Hancock's  figure.    Lettering,  the  same  as  in  figs.  18 
and  19. 


U.  S.  Geological  Survey. 


Geology  of  Kurrka  District,   Plato 


X  r**s^\ 

fo  « 


C'.T)Wdel. 


PLATE    XXII. 

NTTCTJLA  LEVATIFORME 241 

Fig.  1.    Eight  valve. 

la.  Outline.    Natural  size. 

SCHIZODUS  PlNTflENSIS 253 

Figs.  2,  2  a.  Eight  and  left  valves.    Natural  size. 

SCHIZODUS  CURTIFORME 253 

Fig.  3.     Eight  valve.    Natural  size. 

3  a.  Profile  view  of  fig.  3. 

CARDIOLA  f  FILICOSTATA 251 

Fig.  4.     Left  valve,  enlarged  to  two  diameters. 

4  o.  Anterior  view  of  fig.  4. 

SCHIZODUS  DEPARCUS 252 

Fig.  5.     Eight  valve.    Natural  size. 

5  a.  Posterior  profile  view  of  fig.  5. 

SOLENOMYA  CURTA 242 

Fig.  6.  Left  valve.    Natural  size. 

11.  A  more  transverse  right  valve.    Natural  size. 

MYALINA  NEMESIS 237 

Fig.  7.  A  right  valve.    Natural  size.    See  plate  xix,  fig.  5. 

MYALINA  NESSUS 238 

Fig.  8.     A  large  right  valve. 

8  a.  A  smaller  right  valve,  showing  the  anterior  margin. 

EDMONDIA  f  CIRCULARIS , 246 

Fig.  9.  Cast  of  left  valve.    Natural  size. 

MYALINA  CONGENERIS 237 

Fig.  10.  Eight  value.    Natural  size.    See  plate  xix,  fig.  6. 


UNITED   STATES   GEOLOGICAL  SURVEY 


PALEONTOLOGY   OF  THE   EUREKA   DISTRICT      PL.   XXII 


CARBONIFEROUS 


PLATE    XXIII. 

Page. 
BELLEROPHON  MAJUSCULUS 256 

Fig.  1.     View  of  aperture,  callus,  and  body-whorl.    Natural  size. 

1  a.  Lateral  view  of  fig.  1. 

ORTHOCERAS  EUREKENSIS 265 

Fig.  2.     Lateral  view,  showing  curvature  of  the  chambered  portion  of  the  tnbe.    Natural 
size. 

2  a.  One  of  the  septa,  with  the  small  siphuncle  and  areole  about  it. 

HYOLITHES  CARBOXARIA  , 264 

Fig.  3.  Enlargement  to  three  diameters  of  the  type  specimen. 

CONULARIA  MlSSOURIENSIS 264 

Fig.  4.  A  crushed  specimen.     Natural  size. 

MACRODON  HAMILTON^ 243 

Fig.  5.        Cast  of  right  valve.    Natural  size. 
5  a,  &.  Casts  of  left  valve.    Natural  size. 

be.      Enlargement  of  the  surface  of  another  specimen, to  show  the  characteristic 
radiating  and  concentric  lines. 

EDMONDIA  MEDON 245 

Fig.  6.  Right  and  left  valve.    Natural  size. 

SANGUINOLITES  STRIATUS 249 

Fig.  7.  Left  valve.    Natural  size. 


UNITED   STATES   GEOLOGICAL  SURVEY 


PALEONTOLOGY  OF  THE   EUREKA  DISTRICT      PL.   XXIII 


CARBONIFEROUS 


PLATE    XXIV. 

Page. 
LOXONEMA  BELLA 2f>-^ 

Figs.  1, 1  a.  Anterior  and  posterior  sides  of  the  same  shell.    Natural  size. 

PLEUROTOMARI  A  NE VADENSIS 259 

Fig.  2.     Anterior  view  of  a  slightly  crushed  specimen  that  is  denuded  of  most  of  the  outer 

shell. 

2a.  Enlargement  of  a  piece  of  the  outer  surface  of  the  shell,  to  show  the  peripheral 
band  and  surface  characters. 

PLATYOSTOMA  INORNATUM 255 

Figs.  3, 3  a.  Anterior  and  posterior  views  of  the  cast.    Natural  size. 

GRIFFITHIDES  PORTLOCKI 266 

Fig.  4.     Central  portions  of  the  head.     Natural  size. 
4  a.  Pygidium.    Natural  size.  * 

4  b.  Right  free  cheek.     Natural  size. 

MlCRODON  (C. )  CONNATUS 250 

Fig.  5, 5  a.  Right  and  left  valves.     Natural  size. 

BELLEROPHOX  MAJUSCULUS 

Fig.  6.  Dorsal  view  of  a  large  specimen.    A  cross-section  of  the  body-whorl  of  this  speci- 
men is  shown  in  the  text.     See  plate  xxiii,  figs.  1,  1  a. 

PLATYCERAS  Piso 254 

Fig.  7.     Dorsal  view.    Natural  size. 

7  a.  View  of  the  side  denuded  of  the  shell.    Natural  size. 

7b.  The  other  side  of  the  same  specimen,  preserving  the  outer  shell. 

MACROCHEILUS,  sp.  T 260 

Fig.  8.  Anterior  view  of  the  specimen  mentioned  in  the  text.    Natural  size. 

PLATYCERAS  OCCIDENS 254 

Fig.  9.     Dorsal  view  of  a  small  shell,  enlarged  to  two  diameters. 
9 a.  Lateral  view  of  another  shell  similarly  enlarged. 


UNITED   STATES   GEOLOGICAL  SURVEY 


PALEONTOLOGY   OF   THE    EURF.KA    DISTRICT      PL.    XXIV 


CARBONIFEROUS 


